diff --git a/Assets/VRM/Editor/Format/VRMMaterialValidator.cs b/Assets/VRM/Editor/Format/VRMMaterialValidator.cs
index 941e59038..d6c792e65 100644
--- a/Assets/VRM/Editor/Format/VRMMaterialValidator.cs
+++ b/Assets/VRM/Editor/Format/VRMMaterialValidator.cs
@@ -30,7 +30,7 @@ namespace VRM
                 // 
                 // extensions.VRM.materialProperties に記録する
                 // 
-                var prop = UniGLTF.ShaderPropExporter.PreShaderPropExporter.GetPropsForSupportedShader(m.shader.name);
+                var prop = UniGLTF.ShaderPropExporter.PreShaderPropExporter.GetPropsForMToon();
                 foreach (var kv in prop.Properties)
                 {
                     if (kv.ShaderPropertyType == UniGLTF.ShaderPropExporter.ShaderPropertyType.TexEnv)
diff --git a/Assets/VRM/Runtime/IO/VRMMaterialExporter.cs b/Assets/VRM/Runtime/IO/VRMMaterialExporter.cs
index bf021f20b..5b7c9035b 100644
--- a/Assets/VRM/Runtime/IO/VRMMaterialExporter.cs
+++ b/Assets/VRM/Runtime/IO/VRMMaterialExporter.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using UniGLTF;
 using UniGLTF.ShaderPropExporter;
@@ -135,16 +134,16 @@ namespace VRM
                 renderQueue = m.renderQueue,
             };
 
-            if (!PreShaderPropExporter.VRMExtensionShaders.Contains(m.shader.name))
+            if (m.shader.name != MToon.Utils.ShaderName)
             {
                 material.shader = glTF_VRM_Material.VRM_USE_GLTFSHADER;
                 return material;
             }
 
-            var prop = PreShaderPropExporter.GetPropsForSupportedShader(m.shader.name);
+            var prop = PreShaderPropExporter.GetPropsForMToon();
             if (prop == null)
             {
-                Debug.LogWarningFormat("Fail to export shader: {0}", m.shader.name);
+                throw new Exception("arienai");
             }
             else
             {
diff --git a/Assets/VRMShaders/VRM/IO/Runtime/PreShaderPropExporter.cs b/Assets/VRMShaders/VRM/IO/Runtime/PreShaderPropExporter.cs
index 8bc5988cb..9d6cd11ce 100644
--- a/Assets/VRMShaders/VRM/IO/Runtime/PreShaderPropExporter.cs
+++ b/Assets/VRMShaders/VRM/IO/Runtime/PreShaderPropExporter.cs
@@ -25,17 +25,16 @@ namespace UniGLTF.ShaderPropExporter
         }
     }
 
+    /// <summary>
+    /// 今はMToon専用
+    /// </summary>
     public static partial class PreShaderPropExporter
     {
-        public static readonly string[] VRMExtensionShaders = new string[]
-        {
-            "VRM/UnlitTransparentZWrite",
-            "VRM/MToon"
-        };
-
         static Dictionary<string, ShaderProps> m_shaderPropMap;
 
-        public static ShaderProps GetPropsForSupportedShader(string shaderName)
+        const string ShaderName = "VRM/MToon";
+
+        public static ShaderProps GetPropsForMToon()
         {
             if (m_shaderPropMap == null)
             {
@@ -51,19 +50,12 @@ namespace UniGLTF.ShaderPropExporter
             }
 
             ShaderProps props;
-            if (m_shaderPropMap.TryGetValue(shaderName, out props))
+            if (m_shaderPropMap.TryGetValue(ShaderName, out props))
             {
                 return props;
             }
 
-#if UNITY_EDITOR
-            // fallback
-            Debug.LogWarningFormat("{0} is not predefined shader. Use ShaderUtil", shaderName);
-            var shader = Shader.Find(shaderName);
-            return ShaderProps.FromShader(shader);
-#else
-            return null;
-#endif
+            throw new Exception("arienai");
         }
     }
 }