diff --git a/Assets/VRM10/Runtime/IO/Material/Vrm10MToonMaterialExporter.cs b/Assets/VRM10/Runtime/IO/Material/Vrm10MToonMaterialExporter.cs
index 7f50a6b55..633fc2a68 100644
--- a/Assets/VRM10/Runtime/IO/Material/Vrm10MToonMaterialExporter.cs
+++ b/Assets/VRM10/Runtime/IO/Material/Vrm10MToonMaterialExporter.cs
@@ -10,7 +10,7 @@ namespace UniVRM10
 {
     public static class Vrm10MToonMaterialExporter
     {
-        const string MTOON_SPEC_VERSION = "1.0-draft";
+        const string MTOON_SPEC_VERSION = "1.0-beta";
 
         public static bool TryExportMaterialAsMToon(Material src, ITextureExporter textureExporter, out glTFMaterial dst)
         {