diff --git a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
index dd90a264a..2134ec5cb 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
@@ -115,31 +115,49 @@ namespace UniVRM10
             }
         }
 
+        /// <summary>
+        /// SpringboneRuntime が無かった時にデフォルトの runtime を作成する
+        /// 
+        /// - Importer に SpringboneRuntime 引数が無かった時
+        /// - Scene 配置 model のスタートアップ
+        /// 
+        /// </summary>
+        /// <param name="root"></param>
+        /// <returns></returns>
+        internal static IVrm10SpringBoneRuntime MakeSpringboneRuntime(GameObject root)
+        {
+            if (root != null)
+            {
+                var provider = root.GetComponent<IVrm10SpringBoneRuntimeProvider>();
+                if (provider != null)
+                {
+                    // 明示的カスタマイズ
+                    return provider.CreateSpringBoneRuntime();
+                }
+            }
+
+            if (Application.isEditor)
+            {
+                // note: test, timeline などで Singleton(DontDestroyOnLoad) が都合が悪い
+                return new Vrm10FastSpringboneRuntimeStandalone();
+            }
+
+            // default
+            return new Vrm10FastSpringboneRuntime();
+        }
+
         internal Vrm10Runtime MakeRuntime(bool useControlRig)
         {
             if (m_springBoneRuntime == null)
             {
-                // シーン配置モデルが play された
-                var provider = GetComponent<IVrm10SpringBoneRuntimeProvider>();
-                if (provider != null)
-                {
-                    // 明示的カスタマイズ
-                    m_springBoneRuntime = provider.CreateSpringBoneRuntime();
-                }
-                else
-                {
-                    // deafult に fallback
-                    if (Application.isEditor)
-                    {
-                        m_springBoneRuntime = new Vrm10FastSpringboneRuntimeStandalone();
-                    }
-                    else
-                    {
-                        m_springBoneRuntime = new Vrm10FastSpringboneRuntime();
-                    }
-                }
+                // springbone が無い => シーン配置モデルが play されたと見做す
+                m_springBoneRuntime = MakeSpringboneRuntime(gameObject);
                 m_springBoneRuntime.InitializeAsync(this, new ImmediateCaller());
             }
+            else
+            {
+                // importer 内で InitializeAsync が呼び出し済み
+            }
             return new Vrm10Runtime(this, useControlRig, m_springBoneRuntime);
         }
 
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
index c3c05ff38..9e56a7366 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -54,24 +54,20 @@ namespace UniVRM10
                 m_externalMap = new Dictionary<SubAssetKey, UnityEngine.Object>();
             }
 
-            m_springboneRuntime = MakeDefaultRuntime(springboneRuntime, isAssetImport);
-        }
-
-        static IVrm10SpringBoneRuntime MakeDefaultRuntime(IVrm10SpringBoneRuntime runtime, bool isAssetImport)
-        {
-            if (runtime != null)
+            if (springboneRuntime == null)
             {
-                return runtime;
+                if (isAssetImport)
+                {
+                    // 何もしない dummy
+                    springboneRuntime = new Vrm10NopSpringboneRuntime();
+                }
+                else
+                {
+                    // default の SpringboneRuntime を作成する
+                    springboneRuntime = Vrm10Instance.MakeSpringboneRuntime(null);
+                }
             }
-
-            if (isAssetImport)
-            {
-                // 何もしない dummy
-                return new Vrm10NopSpringboneRuntime();
-            }
-
-            // Vrm10Instance.MakeRuntime に移譲
-            return null;
+            m_springboneRuntime = springboneRuntime;
         }
 
         static void AssignHumanoid(List<VrmLib.Node> nodes, UniGLTF.Extensions.VRMC_vrm.HumanBone humanBone, VrmLib.HumanoidBones key)