diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshIO/MeshVertex.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshIO/MeshVertex.cs
index 32c66871f..a3f30ed97 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshIO/MeshVertex.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshIO/MeshVertex.cs
@@ -9,7 +9,7 @@ namespace UniGLTF
     /// そのままGPUにアップロードされる
     /// </summary>
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
-    public readonly struct MeshVertex
+    internal readonly struct MeshVertex
     {
         public readonly Vector3 Position;
         public readonly Vector3 Normal;