diff --git a/Assets/VRM10/Runtime/Components/Expression/ExpressionMerger.cs b/Assets/VRM10/Runtime/Components/Expression/ExpressionMerger.cs
index dcd1c1a18..2c345b432 100644
--- a/Assets/VRM10/Runtime/Components/Expression/ExpressionMerger.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/ExpressionMerger.cs
@@ -9,7 +9,7 @@ namespace UniVRM10
     /// <summary>
     /// ブレンドシェイプを蓄えてまとめて適用するクラス
     /// </summary>
-    internal class ExpressionMerger
+    internal sealed class ExpressionMerger
     {
         /// <summary>
         /// Key から Expression を得る
diff --git a/Assets/VRM10/Runtime/Components/Expression/MaterialValueBindingMerger.cs b/Assets/VRM10/Runtime/Components/Expression/MaterialValueBindingMerger.cs
index 3455c5e1d..3a507492e 100644
--- a/Assets/VRM10/Runtime/Components/Expression/MaterialValueBindingMerger.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/MaterialValueBindingMerger.cs
@@ -7,7 +7,7 @@ namespace UniVRM10
     ///
     /// Base + (A.Target - Base) * A.Weight + (B.Target - Base) * B.Weight ...
     ///
-    internal class MaterialValueBindingMerger
+    internal sealed class MaterialValueBindingMerger
     {
         #region MaterialMap
         /// <summary>
diff --git a/Assets/VRM10/Runtime/Components/Expression/MorphTargetBindingMerger.cs b/Assets/VRM10/Runtime/Components/Expression/MorphTargetBindingMerger.cs
index 3130fb5fc..33a4ed166 100644
--- a/Assets/VRM10/Runtime/Components/Expression/MorphTargetBindingMerger.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/MorphTargetBindingMerger.cs
@@ -7,7 +7,7 @@ namespace UniVRM10
     ///
     /// A.Value * A.Weight + B.Value * B.Weight ...
     ///
-    internal class MorphTargetBindingMerger
+    internal sealed class MorphTargetBindingMerger
     {
         class DictionaryKeyMorphTargetBindingComparer : IEqualityComparer<MorphTargetBinding>
         {
diff --git a/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewMeshItem.cs b/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewMeshItem.cs
index 5ff577908..e5a4348ae 100644
--- a/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewMeshItem.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewMeshItem.cs
@@ -6,7 +6,7 @@ using System.Collections.Generic;
 namespace UniVRM10
 {
     [Serializable]
-    public class PreviewMeshItem
+    public sealed class PreviewMeshItem
     {
         public string Path
         {
diff --git a/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewSceneManager.cs b/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewSceneManager.cs
index 66cd2b2a7..2760242ba 100644
--- a/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewSceneManager.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/Preview/PreviewSceneManager.cs
@@ -9,7 +9,7 @@ namespace UniVRM10
     /// <summary>
     /// プレビュー向けのシーンを管理する
     /// </summary>
-    public class PreviewSceneManager : MonoBehaviour
+    public sealed class PreviewSceneManager : MonoBehaviour
     {
         public GameObject Prefab;
 
diff --git a/Assets/VRM10/Runtime/Components/Expression/PreviewMaterialItem.cs b/Assets/VRM10/Runtime/Components/Expression/PreviewMaterialItem.cs
index 923284020..52944f3f0 100644
--- a/Assets/VRM10/Runtime/Components/Expression/PreviewMaterialItem.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/PreviewMaterialItem.cs
@@ -1,7 +1,9 @@
 using System;
 using System.Collections.Generic;
-using UnityEditor;
 using UnityEngine;
+#if UNITY_EDITOR
+using UnityEditor;
+#endif
 
 namespace UniVRM10
 {
@@ -46,7 +48,7 @@ namespace UniVRM10
     ///
     /// </summary>
     [Serializable]
-    public class PreviewMaterialItem
+    public sealed class PreviewMaterialItem
     {
         public readonly Material Material;
 
diff --git a/Assets/VRM10/Runtime/Components/Expression/VRM10Expression.cs b/Assets/VRM10/Runtime/Components/Expression/VRM10Expression.cs
index f5d61dfec..a1a8a835d 100644
--- a/Assets/VRM10/Runtime/Components/Expression/VRM10Expression.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/VRM10Expression.cs
@@ -5,7 +5,7 @@ using UnityEngine;
 namespace UniVRM10
 {
     [CreateAssetMenu(menuName = "VRM10/Expression")]
-    public class VRM10Expression : ScriptableObject
+    public sealed class VRM10Expression : ScriptableObject
     {
 #if UNITY_EDITOR
         /// <summary>
diff --git a/Assets/VRM10/Runtime/Components/Expression/VRM10ExpressionAvatar.cs b/Assets/VRM10/Runtime/Components/Expression/VRM10ExpressionAvatar.cs
index 4f1ec660e..98e5f2098 100644
--- a/Assets/VRM10/Runtime/Components/Expression/VRM10ExpressionAvatar.cs
+++ b/Assets/VRM10/Runtime/Components/Expression/VRM10ExpressionAvatar.cs
@@ -11,7 +11,7 @@ using UnityEditor;
 namespace UniVRM10
 {
     [CreateAssetMenu(menuName = "VRM10/ExpressionAvatar")]
-    public class VRM10ExpressionAvatar : ScriptableObject
+    public sealed class VRM10ExpressionAvatar : ScriptableObject
     {
         [SerializeField]
         public List<VRM10Expression> Clips = new List<VRM10Expression>();