diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/Awaitable.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/Awaitable.cs
index b199f68e4..eb4a16706 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/Awaitable.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/Awaitable.cs
@@ -5,6 +5,16 @@ using System.Threading.Tasks;
 
 namespace UniGLTF.AltTask
 {
+    /// <summary>
+    /// Importer 向けに Task を wrap した。
+    /// 
+    /// * EditorやUnitTestなどで、Unity の MainLoop を進行させずに 非同期を進行させることが目的
+    /// 
+    /// Global変数 SynchronizationContext.Current を一時的に変更したいのだが、
+    /// システムに予期せぬ副作用を与える可能性があるのでこれを回避。
+    /// UniGLTF.AltTask.TaskQueue.Current に同じ機能を与えて、タスクのPost先を制御することにした。
+    /// </summary>
+
     public interface IAwaiter : INotifyCompletion
     {
         bool IsCompleted { get; }
@@ -86,18 +96,12 @@ namespace UniGLTF.AltTask
             }, null);
         }
 
-        public static Awaitable Delay()
-        {
-            var task = Task.FromResult<object>(default);
-            return new Awaitable(task);
-        }
-
         public static Awaitable<T> Run<T>(Func<T> action)
         {
             return new Awaitable<T>(Task.Run(action));
         }
 
-        public static Awaitable Run<T>(Action action)
+        public static Awaitable Run(Action action)
         {
             return new Awaitable(Task.Run(action));
         }
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs
new file mode 100644
index 000000000..f6410a344
--- /dev/null
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs
@@ -0,0 +1,17 @@
+using System;
+
+namespace UniGLTF.AltTask
+{
+    public static class LoopAwaitable
+    {
+        // TODO
+        // loop スレッド使わないようにしたい
+        public static Awaitable Create()
+        {
+            return Awaitable.Run(() =>
+            {
+                System.Threading.Thread.Sleep(10);
+            });
+        }
+    }
+}
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs.meta b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs.meta
new file mode 100644
index 000000000..125c21d2f
--- /dev/null
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/AltTask/LoopAwaitable.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: db36517c11c455e4b94d9cbb8c1cc3ff
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
index 96b69ba24..bc9828bfb 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
@@ -391,7 +391,7 @@ namespace UniGLTF
                     Nodes.Add(NodeImporter.ImportNode(GLTF.nodes[i], i).transform);
                 }
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("BuildHierarchy"))
             {
@@ -416,7 +416,7 @@ namespace UniGLTF
                     t.SetParent(Root.transform, false);
                 }
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("AnimationImporter"))
             {
@@ -434,7 +434,7 @@ namespace UniGLTF
         protected virtual async Awaitable OnLoadModel()
         {
             Root.name = "GLTF";
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
         }
 
         async Awaitable<MeshWithMaterials> BuildMeshAsync(MeshImporter.MeshContext x, int i)
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
index 5952b9349..ce0bdb40c 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
@@ -660,9 +660,9 @@ namespace UniGLTF
 
             if (recalculateTangents)
             {
-                await Awaitable.Delay();
+                await LoopAwaitable.Create();
                 mesh.RecalculateTangents();
-                await Awaitable.Delay();
+                await LoopAwaitable.Create();
             }
 
             // 先にすべてのマテリアルを作成済みなのでテクスチャーは生成済み。Resultを使ってよい
@@ -672,7 +672,7 @@ namespace UniGLTF
                 Materials = meshContext.MaterialIndices.Select(x => ctx.GetMaterial(x)).ToArray()
             };
 
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
             if (meshContext.BlendShapes.Count > 0)
             {
                 var emptyVertices = new Vector3[mesh.vertexCount];
diff --git a/Assets/VRM/Runtime/IO/VRMImporterContext.cs b/Assets/VRM/Runtime/IO/VRMImporterContext.cs
index 3f4029003..a3ae2051c 100644
--- a/Assets/VRM/Runtime/IO/VRMImporterContext.cs
+++ b/Assets/VRM/Runtime/IO/VRMImporterContext.cs
@@ -61,26 +61,26 @@ namespace VRM
             {
                 await LoadMetaAsync();
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("VRM LoadHumanoid"))
             {
                 LoadHumanoid();
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("VRM LoadBlendShapeMaster"))
             {
                 LoadBlendShapeMaster();
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("VRM LoadSecondary"))
             {
                 VRMSpringUtility.LoadSecondary(Root.transform, Nodes,
                 VRM.secondaryAnimation);
             }
-            await Awaitable.Delay();
+            await LoopAwaitable.Create();
 
             using (MeasureTime("VRM LoadFirstPerson"))
             {