2025年版YouTube MP4変換ツールおすすめ8選（無料・有料）

<style>
/* Critical fix for hero image */
img.hero-image {
  opacity: 1 !important;
  display: block !important;
  visibility: visible !important;
}

.converter-overview {
  background: linear-gradient(135deg, #1976D2 0%, #1565C0 100%);
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  color: white;
}

.converter-overview h3 {
  color: white;
  margin-bottom: 24px;
  text-align: center;
}

.converter-categories {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 24px;
}

.category-card {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 12px;
  padding: 20px;
  backdrop-filter: blur(10px);
  transition: all 0.3s ease;
}

.category-card:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-2px);
}

.category-card h4 {
  color: white;
  margin-bottom: 12px;
  font-size: 1.1em;
}

.category-card p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 0.9em;
  line-height: 1.5;
}

.converter-grid {
  display: flex;
  flex-direction: column;
  gap: 40px;
  margin: 48px auto;
  max-width: 900px;
  padding: 0 20px;
  text-align: left;
}

.converter-card {
  background: #ffffff;
  border: 2px solid #e2e8f0;
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  transition: all 0.3s ease;
  margin-bottom: 24px;
  position: relative;
  text-align: left;
}

.converter-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #1976D2 0%, #1565C0 100%);
  border-radius: 16px 16px 0 0;
}

.converter-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
  border-color: #cbd5e0;
}

.converter-card h4 {
  color: #2d3748;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.3;
  text-align: left;
  margin-top: 0;
  padding-bottom: 8px;
  border-bottom: 1px solid #e2e8f0;
  justify-content: flex-start;
}

.converter-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  flex-shrink: 0;
  margin-right: 4px;
}

.converter-card p {
  color: #4a5568;
  line-height: 1.7;
  margin-bottom: 20px;
  font-size: 1rem;
  text-align: left;
}

.converter-card ul {
  margin: 0;
  padding-left: 20px;
  text-align: left;
}

.converter-card li {
  color: #4a5568;
  line-height: 1.6;
  margin-bottom: 8px;
  font-size: 0.95rem;
  text-align: left;
}

.pros-cons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 20px 0;
}

.pros, .cons {
  padding: 16px;
  border-radius: 8px;
}

.pros {
  background: #f0fff4;
  border: 1px solid #9ae6b4;
}

.cons {
  background: #fff5f5;
  border: 1px solid #fed7d7;
}

.pros h5, .cons h5 {
  margin: 0 0 12px 0;
  font-size: 0.9rem;
  font-weight: 600;
}

.pros h5 {
  color: #22543d;
}

.cons h5 {
  color: #c53030;
}

.pros ul, .cons ul {
  margin: 0;
  padding-left: 16px;
}

.pros li, .cons li {
  font-size: 0.85rem;
  margin-bottom: 6px;
}

.stats-showcase {
  display: flex;
  flex-direction: row;
  gap: 15px;
  margin: 24px 0;
  max-width: 100%;
  justify-content: center;
  flex-wrap: nowrap;
}

.stat-card {
  background: linear-gradient(135deg, #1976D2 0%, #1565C0 100%);
  color: white;
  padding: 20px;
  border-radius: 12px;
  text-align: center;
  flex: 1;
  min-width: 0;
}

.stat-number {
  font-size: 2.5rem;
  font-weight: bold;
  line-height: 1;
}

.stat-label {
  font-size: 0.9rem;
  opacity: 0.9;
  margin-top: 8px;
}

.comparison-table-wrapper {
  margin: 2rem 0;
  overflow-x: auto;
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  background: white;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.comparison-table th {
  padding: 1rem 0.75rem;
  text-align: left;
  font-weight: 600;
  border: none;
  background: linear-gradient(135deg, #1976D2 0%, #1565C0 100%);
  color: white;
}

.comparison-table td {
  padding: 1rem 0.75rem;
  border: none;
  border-bottom: 1px solid #f1f5f9;
  transition: all 0.2s ease;
}

.comparison-table tr:hover td {
  background-color: #f8fafc;
}

.faq-container {
  background: #f8fafc;
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  border: 1px solid #e2e8f0;
}

.faq-container h3 {
  color: #2d3748;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid #e2e8f0;
}

@media (max-width: 1024px) {
  .stats-showcase {
    gap: 12px;
  }
  
  .stat-card {
    padding: 16px;
  }
  
  .stat-number {
    font-size: 2rem;
  }
  
  .stat-label {
    font-size: 0.8rem;
  }
}

@media (max-width: 768px) {
  .converter-categories {
    grid-template-columns: 1fr;
  }
  
  .converter-card {
    padding: 28px 24px;
    border-radius: 16px;
    margin: 0 8px;
  }
  
  .converter-card h4 {
    font-size: 1.2rem;
    gap: 16px;
    align-items: center;
  }
  
  .converter-icon {
    width: 48px;
    height: 48px;
    font-size: 24px;
    margin-top: 0;
  }
  
  .converter-card p {
    font-size: 1rem;
    text-align: left;
    line-height: 1.7;
  }
  
  .converter-grid {
    gap: 32px;
    margin: 40px auto;
    padding: 0 12px;
    max-width: 100%;
  }
  
  .stats-showcase {
    gap: 10px;
  }
  
  .stat-card {
    padding: 14px;
  }
  
  .stat-number {
    font-size: 1.8rem;
  }
  
  .stat-label {
    font-size: 0.75rem;
  }
  
  .pros-cons {
    grid-template-columns: 1fr;
  }
}


@media (max-width: 480px) {
  .converter-card {
    padding: 24px 20px;
    border-radius: 12px;
  }
  
  .converter-card h4 {
    font-size: 1.1rem;
    gap: 12px;
  }
  
  .converter-icon {
    width: 40px;
    height: 40px;
    font-size: 20px;
  }
  
  .converter-grid {
    gap: 24px;
    padding: 0 8px;
  }
  
  .stats-showcase {
    flex-direction: column;
    max-width: 280px;
    margin-left: auto;
    margin-right: auto;
  }
  
  .stat-card {
    padding: 20px;
  }
  
  .stat-number {
    font-size: 2.5rem;
  }
  
  .stat-label {
    font-size: 0.9rem;
  }
}

/* New UI Components for Introduction Section */
.intro-highlight-box {
  background: linear-gradient(135deg, #E3F2FD 0%, #F3E5F5 100%);
  border: 1px solid #1976D2;
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  display: flex;
  align-items: center;
  gap: 24px;
  box-shadow: 0 8px 25px rgba(25, 118, 210, 0.1);
}

.intro-icon {
  font-size: 3rem;
  flex-shrink: 0;
}

.intro-content h3 {
  color: #1976D2;
  margin: 0 0 16px 0;
  font-size: 1.5rem;
  font-weight: 700;
}

.intro-content p {
  color: #424242;
  margin: 0;
  font-size: 1.1rem;
  line-height: 1.6;
}

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin: 32px 0;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.benefit-card {
  background: #FFFFFF;
  border: 1px solid #E0E0E0;
  border-radius: 12px;
  padding: 24px;
  text-align: center;
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  transition: all .3s ease;
}

.benefit-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 25px rgba(0,0,0,.15);
  border-color: #1976D2;
}

.benefit-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
  display: block;
}

.benefit-card h4 {
  color: #1976D2;
  margin: 0 0 12px 0;
  font-size: 1.25rem;
  font-weight: 600;
}

.benefit-card p {
  color: #666;
  margin: 0;
  line-height: 1.5;
}

.explanation-section {
  background: #F8F9FA;
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  border: 1px solid #E0E0E0;
}

.explanation-visual {
  margin-bottom: 24px;
}

.conversion-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.flow-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  background: #FFFFFF;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  min-width: 120px;
}

.step-icon {
  font-size: 2rem;
}

.flow-step span {
  font-weight: 600;
  color: #1976D2;
  font-size: 0.9rem;
}

.flow-arrow {
  font-size: 1.5rem;
  color: #1976D2;
  font-weight: bold;
}

.explanation-content p {
  color: #424242;
  font-size: 1.1rem;
  margin-bottom: 20px;
}

.use-cases {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.use-case {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: #FFFFFF;
  border-radius: 8px;
  border-left: 4px solid #1976D2;
}

.use-case-icon {
  font-size: 1.25rem;
}

.criteria-section {
  margin: 32px 0;
}

.criteria-section h3 {
  color: #1976D2;
  text-align: center;
  margin-bottom: 32px;
  font-size: 1.75rem;
}

.criteria-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.criteria-card {
  background: #FFFFFF;
  border: 1px solid #E0E0E0;
  border-radius: 12px;
  padding: 24px;
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  transition: all .3s ease;
}

.criteria-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,.12);
  border-color: #1976D2;
}

.criteria-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.criteria-icon {
  font-size: 1.5rem;
}

.criteria-card h4 {
  color: #1976D2;
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
}

.criteria-card p {
  color: #666;
  margin: 0;
  line-height: 1.5;
}

.guide-preview {
  background: linear-gradient(135deg, #1976D2 0%, #1565C0 100%);
  color: white;
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  text-align: center;
}

.guide-preview h3 {
  color: white;
  margin: 0 0 24px 0;
  font-size: 1.5rem;
}

.preview-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 600px;
  margin: 0 auto;
}

.preview-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  backdrop-filter: blur(10px);
}

.preview-number {
  background: white;
  color: #1976D2;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
}

/* Responsive Design for New Components */
@media (max-width: 1024px) {
  .benefits-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  .intro-highlight-box {
    flex-direction: column;
    text-align: center;
    padding: 24px;
  }
  
  .intro-icon {
    font-size: 2.5rem;
  }
  
  .benefits-grid {
    grid-template-columns: 1fr;
    gap: 16px;
    max-width: 100%;
  }
  
  .conversion-flow {
    flex-direction: column;
    gap: 12px;
  }
  
  .flow-arrow {
    transform: rotate(90deg);
  }
  
  .criteria-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  .preview-list {
    gap: 12px;
  }
  
  .preview-item {
    padding: 12px 16px;
  }
}

@media (max-width: 480px) {
  .intro-highlight-box {
    padding: 20px;
  }
  
  .intro-content h3 {
    font-size: 1.25rem;
  }
  
  .intro-content p {
    font-size: 1rem;
  }
  
  .benefit-card {
    padding: 20px;
  }
  
  .explanation-section {
    padding: 24px;
  }
  
  .criteria-card {
    padding: 20px;
  }
  
  .guide-preview {
    padding: 24px;
  }
}

/* How-to Section Styles */
.how-to-section {
  background: #F8F9FA;
  border-radius: 16px;
  padding: 32px;
  margin: 32px 0;
  border: 1px solid #E0E0E0;
}

.how-to-header {
  text-align: center;
  margin-bottom: 32px;
}

.how-to-header h3 {
  color: #1976D2;
  margin: 0 0 12px 0;
  font-size: 1.75rem;
  font-weight: 700;
}

.how-to-header p {
  color: #666;
  margin: 0;
  font-size: 1.1rem;
}

.steps-container {
  display: flex;
  flex-direction: column;
  gap: 20px;
  max-width: 800px;
  margin: 0 auto;
}

.step-item {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  background: #FFFFFF;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  border-left: 4px solid #1976D2;
  transition: all .3s ease;
}

.step-item:hover {
  transform: translateX(4px);
  box-shadow: 0 8px 20px rgba(0,0,0,.12);
}

.step-number {
  background: #1976D2;
  color: white;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.step-content {
  flex: 1;
}

.step-icon {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.step-content h4 {
  color: #1976D2;
  margin: 0 0 8px 0;
  font-size: 1.1rem;
  font-weight: 600;
}

.step-content p {
  color: #666;
  margin: 0;
  line-height: 1.5;
}

.pro-tip {
  background: linear-gradient(135deg, #FFF3E0 0%, #FFE0B2 100%);
  border: 1px solid #FF9800;
  border-radius: 12px;
  padding: 20px;
  margin-top: 32px;
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.tip-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.tip-content h4 {
  color: #E65100;
  margin: 0 0 8px 0;
  font-size: 1rem;
  font-weight: 600;
}

.tip-content p {
  color: #BF360C;
  margin: 0;
  line-height: 1.5;
  font-size: 0.95rem;
}

/* Advanced Features Section Styles */
.features-section {
  margin: 32px 0;
}

.features-header {
  text-align: center;
  margin-bottom: 32px;
}

.features-header h3 {
  color: #1976D2;
  margin: 0 0 12px 0;
  font-size: 1.75rem;
  font-weight: 700;
}

.features-header p {
  color: #666;
  margin: 0;
  font-size: 1.1rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 800px;
  margin: 0 auto;
}

.feature-card {
  background: #FFFFFF;
  border: 1px solid #E0E0E0;
  border-radius: 12px;
  padding: 24px;
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  transition: all .3s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 25px rgba(0,0,0,.15);
  border-color: #1976D2;
}

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
  display: block;
}

.feature-content h4 {
  color: #1976D2;
  margin: 0 0 12px 0;
  font-size: 1.25rem;
  font-weight: 600;
}

.feature-content p {
  color: #666;
  margin: 0 0 16px 0;
  line-height: 1.5;
}

.feature-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tool-tag {
  background: #E3F2FD;
  color: #1976D2;
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 500;
}

/* Responsive Design for New Sections */
@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  .how-to-section {
    padding: 24px;
  }
  
  .step-item {
    padding: 20px;
    gap: 16px;
  }
  
  .step-number {
    width: 36px;
    height: 36px;
    font-size: 1rem;
  }
  
  .pro-tip {
    padding: 16px;
    gap: 12px;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
    gap: 20px;
    max-width: 100%;
  }
  
  .feature-card {
    padding: 20px;
  }
}

@media (max-width: 480px) {
  .how-to-section {
    padding: 20px;
  }
  
  .step-item {
    padding: 16px;
    gap: 12px;
  }
  
  .step-number {
    width: 32px;
    height: 32px;
    font-size: 0.9rem;
  }
  
  .step-content h4 {
    font-size: 1rem;
  }
  
  .feature-card {
    padding: 16px;
  }
  
  .feature-icon {
    font-size: 2rem;
  }
}
</style>

互換性のない形式で止まっている魅力的なYouTubeビデオをダウンロードしたことはありませんか？あなたは一人ではありません。ほとんどのデバイスはYouTubeのネイティブ形式に苦労しており、再生の問題や互換性の問題に不満を感じています。

これは、2025年の**最高のYouTube to MP4変換ツール**に関する決定版ガイドです。シームレスなビデオダウンロードを毎回実現する完璧なコンバーターを見つけるために、すべてのプラットフォームでトップアプリケーションをテストしました。

**最高の無料YouTube to MP4変換ツール**、信頼できる**デスクトップソフトウェア**、または便利な**オンラインツール**をお探しの場合でも、包括的なレビューとパフォーマンスの比較で対応します。

<div class="converter-overview">
<h3>YouTube to MP4コンバーターの主なカテゴリー：</h3>
<div class="converter-categories">
<div class="category-card">
<h4>🌐 オンラインコンバーター</h4>
<p>ダウンロードなしでインスタント変換できるWebベースのツール</p>
</div>
<div class="category-card">
<h4>💻 デスクトップソフトウェア</h4>
<p>高度な機能とバッチ処理を備えた強力なアプリケーション</p>
</div>
<div class="category-card">
<h4>📱 モバイルアプリ</h4>
<p>外出先でのビデオダウンロードに便利なコンバーター</p>
</div>
<div class="category-card">
<h4>⚡ 速度と品質</h4>
<p>高品質の出力を維持しながら高速変換</p>
</div>
</div>
</div>

## 概要：上位のYouTube to MP4コンバーターの比較

<div class="comparison-table-wrapper">
<table class="comparison-table">
<thead>
<tr>
<th>コンバーター</th>
<th>タイプ</th>
<th>プラットフォーム</th>
<th>品質</th>
<th>速度</th>
<th>価格</th>
</tr>
</thead>
<tbody>
<tr>
<td><strong>OnlineVideoConverter.com</strong></td>
<td>オンライン</td>
<td>Webブラウザ</td>
<td>最大4K</td>
<td>高速</td>
<td>無料</td>
</tr>
<tr>
<td><strong>YT Convert</strong></td>
<td>オンライン</td>
<td>Webブラウザ</td>
<td>HD/4K</td>
<td>高速</td>
<td>無料</td>
</tr>
<tr>
<td><strong>YouTube4KDownloader</strong></td>
<td>デスクトップ</td>
<td>Windows/Mac</td>
<td>4K/HD</td>
<td>非常に高速</td>
<td>無料</td>
</tr>
<tr>
<td><strong>EaseUS Video Converter</strong></td>
<td>デスクトップ</td>
<td>Windows/Mac</td>
<td>最大4K</td>
<td>高速</td>
<td>フリーミアム</td>
</tr>
<tr>
<td><strong>Wave.video</strong></td>
<td>オンライン</td>
<td>Webブラウザ</td>
<td>HD</td>
<td>普通</td>
<td>フリーミアム</td>
</tr>
<tr>
<td><strong>Fastest YouTube Downloader</strong></td>
<td>デスクトップ</td>
<td>Windows</td>
<td>HD</td>
<td>非常に高速</td>
<td>無料</td>
</tr>
<tr>
<td><strong>VideoProc Converter</strong></td>
<td>デスクトップ</td>
<td>Windows/Mac</td>
<td>最大4K</td>
<td>高速</td>
<td>フリーミアム</td>
</tr>
<tr>
<td><strong>MP3Studio YouTube Downloader</strong></td>
<td>デスクトップ</td>
<td>Windows</td>
<td>HD</td>
<td>普通</td>
<td>無料</td>
</tr>
</tbody>
</table>
</div>

<div class="stats-showcase">
<div class="stat-card">
<div class="stat-number">8</div>
<div class="stat-label">テストされた上位コンバーター</div>
</div>
<div class="stat-card">
<div class="stat-number">4