diff --git a/app/Utilities/Formatter.php b/app/Utilities/Formatter.php
index 0adee69..6098388 100644
--- a/app/Utilities/Formatter.php
+++ b/app/Utilities/Formatter.php
@@ -75,4 +75,21 @@ class Formatter
 
         return $url;
     }
+
+    /**
+     * imgタグのsrcsetで使用できる形式で、プロフィール画像URLを生成します。
+     * @param object $user Userなど、getProfileImageUrl()が実装されているオブジェクト
+     * @param int $baseSize 1x解像度における画像サイズ
+     * @param int $maxDensity 最高密度
+     * @return string srcset用の文字列
+     */
+    public function profileImageSrcSet($user, int $baseSize, int $maxDensity = 3)
+    {
+        $srcset = [];
+        for ($i = 1; $i <= $maxDensity; $i++) {
+            $srcset[] = $user->getProfileImageUrl($baseSize * $i) . " {$i}x";
+        }
+
+        return implode(',', $srcset);
+    }
 }
diff --git a/resources/views/components/ejaculation.blade.php b/resources/views/components/ejaculation.blade.php
index 9635273..3d17540 100644
--- a/resources/views/components/ejaculation.blade.php
+++ b/resources/views/components/ejaculation.blade.php
@@ -1,7 +1,7 @@
 <!-- span -->
 <div>
     <h5>
-        <a href="{{ route('user.profile', ['id' => $ejaculation->user->name]) }}" class="text-dark"><img src="{{ $ejaculation->user->getProfileImageUrl(30) }}" width="30" height="30" class="rounded d-inline-block align-bottom"> <bdi>{{ $ejaculation->user->display_name }}</bdi></a>
+        <a href="{{ route('user.profile', ['id' => $ejaculation->user->name]) }}" class="text-dark"><img src="{{ $ejaculation->user->getProfileImageUrl(30) }}" srcset="{{ Formatter::profileImageSrcSet($ejaculation->user, 30) }}" width="30" height="30" class="rounded d-inline-block align-bottom"> <bdi>{{ $ejaculation->user->display_name }}</bdi></a>
         <a href="{{ route('checkin.show', ['id' => $ejaculation->id]) }}" class="text-muted"><small>{{ $ejaculation->ejaculated_date->format('Y/m/d H:i') }}</small></a>
     </h5>
 </div>
@@ -39,7 +39,7 @@
         <div class="like-users flex-grow-1 overflow-hidden">
             @foreach ($ejaculation->likes as $like)
                 @if ($like->user !== null)
-                    <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(30) }}" width="30" height="30" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
+                    <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(30) }}" srcset="{{ Formatter::profileImageSrcSet($like->user, 30) }}" width="30" height="30" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
                 @endif
             @endforeach
         </div>
diff --git a/resources/views/components/profile.blade.php b/resources/views/components/profile.blade.php
index 676764f..253e187 100644
--- a/resources/views/components/profile.blade.php
+++ b/resources/views/components/profile.blade.php
@@ -1,6 +1,6 @@
 <div class="card mb-4">
     <div class="card-body">
-        <img src="{{ $user->getProfileImageUrl(128) }}" class="rounded mb-1">
+        <img src="{{ $user->getProfileImageUrl(128) }}" srcset="{{ Formatter::profileImageSrcSet($user, 128) }}" class="rounded mb-1">
         <h4 class="card-title">
             <a class="text-dark" href="{{ route('user.profile', ['name' => $user->name]) }}">{{ $user->display_name }}</a>
         </h4>
diff --git a/resources/views/ejaculation/show.blade.php b/resources/views/ejaculation/show.blade.php
index 8d870e0..1f7d3d7 100644
--- a/resources/views/ejaculation/show.blade.php
+++ b/resources/views/ejaculation/show.blade.php
@@ -67,7 +67,7 @@
                                 <div class="like-users-tall flex-grow-1 overflow-hidden">
                                     @foreach ($ejaculation->likes as $like)
                                         @if ($like->user !== null)
-                                            <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(36) }}" width="36" height="36" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
+                                            <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(36) }}" srcset="{{ Formatter::profileImageSrcSet($like->user, 36) }}" width="36" height="36" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
                                         @endif
                                     @endforeach
                                 </div>
diff --git a/resources/views/home.blade.php b/resources/views/home.blade.php
index 5b0be88..0aceb12 100644
--- a/resources/views/home.blade.php
+++ b/resources/views/home.blade.php
@@ -10,7 +10,7 @@
             <div class="card mb-4">
                 <div class="card-body">
                     <div class="d-flex flex-row align-items-end mb-4">
-                        <img src="{{ Auth::user()->getProfileImageUrl(48) }}" class="rounded mr-2">
+                        <img src="{{ Auth::user()->getProfileImageUrl(48) }}" srcset="{{ Formatter::profileImageSrcSet(Auth::user(), 48) }}" class="rounded mr-2">
                         <div class="d-flex flex-column overflow-hidden">
                             <h5 class="card-title text-truncate">
                                 <a class="text-dark" href="{{ route('user.profile', ['name' => Auth::user()->name]) }}">{{ Auth::user()->display_name }}</a>
diff --git a/resources/views/layouts/base.blade.php b/resources/views/layouts/base.blade.php
index 201ee8d..786eaa3 100644
--- a/resources/views/layouts/base.blade.php
+++ b/resources/views/layouts/base.blade.php
@@ -40,7 +40,7 @@
             <div class="d-lg-none navbar-nav">
                 <div class="nav-item dropdown">
                     <a href="#" class="nav-link dropdown-toggle p-2" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
-                        <img src="{{ Auth::user()->getProfileImageUrl(30) }}" width="30" height="30" class="rounded d-inline-block align-top">
+                        <img src="{{ Auth::user()->getProfileImageUrl(30) }}" srcset="{{ Formatter::profileImageSrcSet(Auth::user(), 30) }}" width="30" height="30" class="rounded d-inline-block align-top">
                     </a>
                     <div class="dropdown-menu dropdown-menu-right position-absolute" aria-labelledby="navbarDropdownMenuLink" id="navbarAccountDropdownSp">
                         <a href="{{ route('user.profile', ['name' => Auth::user()->name]) }}" class="dropdown-item text-truncate">
@@ -103,7 +103,7 @@
                     <ul class="navbar-nav">
                         <li class="nav-item dropdown">
                             <a href="#" class="nav-link dropdown-toggle" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
-                                <img src="{{ Auth::user()->getProfileImageUrl(30) }}" width="30" height="30" class="rounded d-inline-block align-top">
+                                <img src="{{ Auth::user()->getProfileImageUrl(30) }}" srcset="{{ Formatter::profileImageSrcSet(Auth::user(), 30) }}" width="30" height="30" class="rounded d-inline-block align-top">
                             </a>
                             <div class="dropdown-menu dropdown-menu-right" aria-labelledby="navbarDropdownMenuLink">
                                 <a href="{{ route('user.profile', ['name' => Auth::user()->name]) }}" class="dropdown-item">
diff --git a/resources/views/setting/profile.blade.php b/resources/views/setting/profile.blade.php
index deff717..fb34a22 100644
--- a/resources/views/setting/profile.blade.php
+++ b/resources/views/setting/profile.blade.php
@@ -9,7 +9,7 @@
         {{ csrf_field() }}
         <div class="from-group">
             <label for="name">アイコン</label>
-            <img src="{{ Auth::user()->getProfileImageUrl(128) }}" class="rounded d-block">
+            <img src="{{ Auth::user()->getProfileImageUrl(128) }}" srcset="{{ Formatter::profileImageSrcSet(Auth::user(), 128) }}" class="rounded d-block">
             <small class="form-text text-muted">変更は<a href="https://gravatar.com/" target="_blank">Gravatar</a>から行えます。</small>
         </div>
         <div class="from-group mt-3">
diff --git a/resources/views/user/profile.blade.php b/resources/views/user/profile.blade.php
index 056a53e..6a35eec 100644
--- a/resources/views/user/profile.blade.php
+++ b/resources/views/user/profile.blade.php
@@ -73,7 +73,7 @@
                         <div class="like-users flex-grow-1 overflow-hidden">
                             @foreach ($ejaculation->likes as $like)
                                 @if ($like->user !== null)
-                                    <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(30) }}" width="30" height="30" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
+                                    <a href="{{ route('user.profile', ['name' => $like->user->name]) }}"><img src="{{ $like->user->getProfileImageUrl(30) }}" srcset="{{ Formatter::profileImageSrcSet($like->user, 30) }}" width="30" height="30" class="rounded" data-toggle="tooltip" data-placement="bottom" title="{{ $like->user->display_name }}"></a>
                                 @endif
                             @endforeach
                         </div>
diff --git a/tests/Unit/Utilities/FormatterTest.php b/tests/Unit/Utilities/FormatterTest.php
index fca2fba..843e60f 100644
--- a/tests/Unit/Utilities/FormatterTest.php
+++ b/tests/Unit/Utilities/FormatterTest.php
@@ -54,4 +54,20 @@ class FormatterTest extends TestCase
         $url = 'http://example.com/path/to?foo=bar&hoge=fuga#';
         $this->assertEquals('http://example.com/path/to?foo=bar&hoge=fuga', $formatter->normalizeUrl($url));
     }
+
+    public function testProfileImageSrcSet()
+    {
+        $formatter = new Formatter();
+        $profileImageProvider = new class() {
+            public function getProfileImageUrl(int $size)
+            {
+                return "https://example.com/$size.png";
+            }
+        };
+
+        $this->assertSame(
+            'https://example.com/128.png 1x,https://example.com/256.png 2x',
+            $formatter->profileImageSrcSet($profileImageProvider, 128, 2)
+        );
+    }
 }