diff --git a/Assets/UniGLTF/Runtime/MeshUtility/BoneMeshEraser.cs b/Assets/UniGLTF/Runtime/MeshUtility/BoneMeshEraser.cs
index fd34c2584..88d614ca3 100644
--- a/Assets/UniGLTF/Runtime/MeshUtility/BoneMeshEraser.cs
+++ b/Assets/UniGLTF/Runtime/MeshUtility/BoneMeshEraser.cs
@@ -131,7 +131,7 @@ namespace UniGLTF.MeshUtility
         /// <param name="boneWeights"></param>
         /// <param name="eraseBoneIndices"></param>
         /// <returns></returns>
-        public static int[] GetExcludedIndices(int[] indices, BoneWeight[] boneWeights, int[] eraseBoneIndices)
+        static int[] GetExcludedIndices(int[] indices, BoneWeight[] boneWeights, int[] eraseBoneIndices)
         {
             var count = ExcludeTriangles(indices, boneWeights, eraseBoneIndices);
             var dst = new int[count];
diff --git a/Assets/UniGLTF/Runtime/MeshUtility/MeshIntegrator.cs b/Assets/UniGLTF/Runtime/MeshUtility/MeshIntegrator.cs
index b24c16ce1..8ecb955fe 100644
--- a/Assets/UniGLTF/Runtime/MeshUtility/MeshIntegrator.cs
+++ b/Assets/UniGLTF/Runtime/MeshUtility/MeshIntegrator.cs
@@ -165,6 +165,12 @@ namespace UniGLTF.MeshUtility
 
         public void Push(SkinnedMeshRenderer renderer)
         {
+            if (renderer == null)
+            {
+                // Debug.LogWarningFormat("{0} was destroyed", renderer);
+                return;
+            }
+
             var mesh = renderer.sharedMesh;
             if (mesh == null)
             {
diff --git a/Assets/VRM10/Runtime/Components/VRM10Object/VRM10ObjectFirstPerson.cs b/Assets/VRM10/Runtime/Components/VRM10Object/VRM10ObjectFirstPerson.cs
index af956c287..e8db4b7e7 100644
--- a/Assets/VRM10/Runtime/Components/VRM10Object/VRM10ObjectFirstPerson.cs
+++ b/Assets/VRM10/Runtime/Components/VRM10Object/VRM10ObjectFirstPerson.cs
@@ -29,7 +29,7 @@ namespace UniVRM10
             }
         }
 
-        public static int[] GetBonesThatHasAncestor(SkinnedMeshRenderer smr, Transform ancestor)
+        static int[] GetBonesThatHasAncestor(SkinnedMeshRenderer smr, Transform ancestor)
         {
             var eraseBones = smr.bones
             .Where(x => x.Ancestor().Any(y => y == ancestor))
@@ -38,24 +38,46 @@ namespace UniVRM10
             return eraseBones;
         }
 
+        public static async Task<Mesh> CreateErasedMeshAsync(SkinnedMeshRenderer smr,
+            Transform firstPersonBone,
+            IAwaitCaller awaitCaller)
+        {
+            var eraseBones = GetBonesThatHasAncestor(smr, firstPersonBone);
+            if (eraseBones.Any())
+            {
+                return await BoneMeshEraser.CreateErasedMeshAsync(smr.sharedMesh, eraseBones, awaitCaller);
+            }
+            else
+            {
+                return null;
+            }
+        }
+
         // <summary>
         // 頭部を取り除いたモデルを複製する
         // </summary>
         // <parameter>renderer: 元になるSkinnedMeshRenderer</parameter>
         // <parameter>eraseBones: 削除対象になるボーンのindex</parameter>
-        private async static Task<SkinnedMeshRenderer> CreateHeadlessMeshAsync(SkinnedMeshRenderer renderer, int[] eraseBones, IAwaitCaller awaitCaller)
+        public async static Task<SkinnedMeshRenderer> CreateHeadlessMeshAsync(SkinnedMeshRenderer renderer,
+            Transform firstPersonBone, IAwaitCaller awaitCaller)
         {
-            var mesh = await BoneMeshEraser.CreateErasedMeshAsync(renderer.sharedMesh, eraseBones, awaitCaller);
-
-            var go = new GameObject("_headless_" + renderer.name);
-            var erased = go.AddComponent<SkinnedMeshRenderer>();
-            erased.enabled = false; // hide
-            erased.sharedMesh = mesh;
-            erased.sharedMaterials = renderer.sharedMaterials;
-            erased.bones = renderer.bones;
-            erased.rootBone = renderer.rootBone;
-
-            return erased;
+            var mesh = await CreateErasedMeshAsync(renderer, firstPersonBone, awaitCaller);
+            if (mesh != null)
+            {
+                var go = new GameObject("_headless_" + renderer.name);
+                var erased = go.AddComponent<SkinnedMeshRenderer>();
+                erased.enabled = false; // hide
+                erased.sharedMesh = mesh;
+                erased.sharedMaterials = renderer.sharedMaterials;
+                erased.bones = renderer.bones;
+                erased.rootBone = renderer.rootBone;
+                return erased;
+            }
+            else
+            {
+                // 削除対象が含まれないので何もしない
+                return null;
+            }
         }
 
         bool m_done;
@@ -70,14 +92,13 @@ namespace UniVRM10
                     {
                         if (x.GetRenderer(go.transform) is SkinnedMeshRenderer smr)
                         {
-                            var eraseBones = GetBonesThatHasAncestor(smr, firstPersonBone);
-                            if (eraseBones.Any())
-                            {
-                                // オリジナルのモデルを３人称用にする                                
-                                smr.gameObject.layer = layer.ThirdPersonOnly;
+                            // オリジナルのモデルを３人称用にする                                
+                            smr.gameObject.layer = layer.ThirdPersonOnly;
 
-                                // 頭を取り除いた複製モデルを作成し、１人称用にする
-                                var headless = await CreateHeadlessMeshAsync(smr, eraseBones, awaitCaller);
+                            // 頭を取り除いた複製モデルを作成し、１人称用にする
+                            var headless = await CreateHeadlessMeshAsync(smr, firstPersonBone, awaitCaller);
+                            if (headless != null)
+                            {
                                 headless.gameObject.layer = layer.FirstPersonOnly;
                                 headless.transform.SetParent(smr.transform, false);
                                 if (runtime != null)
@@ -85,10 +106,6 @@ namespace UniVRM10
                                     runtime.AddRenderer(headless);
                                 }
                             }
-                            else
-                            {
-                                // 削除対象が含まれないので何もしない
-                            }
                         }
                         else if (x.GetRenderer(go.transform) is MeshRenderer mr)
                         {
diff --git a/Assets/VRM10/Runtime/MeshUtility/Vrm10MeshUtility.cs b/Assets/VRM10/Runtime/MeshUtility/Vrm10MeshUtility.cs
index 7f3a6fa91..39614d2d9 100644
--- a/Assets/VRM10/Runtime/MeshUtility/Vrm10MeshUtility.cs
+++ b/Assets/VRM10/Runtime/MeshUtility/Vrm10MeshUtility.cs
@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using UniGLTF;
-using UniGLTF.Extensions.VRMC_vrm;
 using UniGLTF.MeshUtility;
 using UniHumanoid;
 using UnityEngine;
@@ -122,6 +120,10 @@ namespace UniVRM10
 
         void RemoveComponent<T>(T c) where T : Component
         {
+            if (c == null)
+            {
+                return;
+            }
             var t = c.transform;
             if (Application.isPlaying)
             {
@@ -225,12 +227,40 @@ namespace UniVRM10
 
             {
                 // TODO: UNDO            
+                var results = new List<MeshIntegrationResult>();
                 foreach (var group in copy)
                 {
                     var result = MeshIntegrator.Integrate(group, SplitByBlendShape
                         ? MeshIntegrator.BlendShapeOperation.Split
                         : MeshIntegrator.BlendShapeOperation.None);
+                    results.Add(result);
 
+                    result.AddIntegratedRendererTo(go);
+
+                    if (generateFirstPerson && group.Name == "auto")
+                    {
+                        Debug.Log("generateFirstPerson");
+                        var firstPersonBone = vrmInstance.Humanoid.Head;
+                        var task = VRM10ObjectFirstPerson.CreateErasedMeshAsync(
+                            result.IntegratedRenderer,
+                            firstPersonBone,
+                            new ImmediateCaller());
+                        task.Wait();
+
+                        if (task.Result != null)
+                        {
+                            result.IntegratedRenderer.sharedMesh = task.Result;
+                            result.IntegratedRenderer.name = "auto.headless";
+                        }
+                        else
+                        {
+                            Debug.LogWarning("no result");
+                        }
+                    }
+                }
+
+                foreach (var result in results)
+                {
                     foreach (var r in result.SourceMeshRenderers)
                     {
                         RemoveComponent(r);
@@ -239,27 +269,6 @@ namespace UniVRM10
                     {
                         RemoveComponent(r);
                     }
-
-                    result.AddIntegratedRendererTo(go);
-
-                    if (generateFirstPerson && group.Name == "auto")
-                    {
-                        var firstPersonBone = vrmInstance.Humanoid.Head;
-                        var eraseBones = VRM10ObjectFirstPerson.GetBonesThatHasAncestor(
-                            result.IntegratedRenderer, firstPersonBone);
-                        var task = BoneMeshEraser.CreateErasedMeshAsync(result.MeshMap.Integrated, eraseBones,
-                            new ImmediateCaller());
-                        task.Wait();
-
-                        if (task.Result.vertexCount > 0)
-                        {
-                            var headless = new GameObject("auto.headless");
-                            var smr = headless.AddComponent<SkinnedMeshRenderer>();
-                            smr.sharedMesh = task.Result;
-
-                            headless.transform.SetParent(go.transform);
-                        }
-                    }
                 }
             }
         }