diff --git a/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs b/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
index 2ea4400cd..bbffdb6aa 100644
--- a/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
+++ b/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
@@ -72,6 +72,18 @@ namespace UniGLTF
             {
                 return cv.ComponentType;
             }
+            else if (typeof(T) == typeof(sbyte))
+            {
+                return glComponentType.BYTE;
+            }
+            else if (typeof(T) == typeof(byte))
+            {
+                return glComponentType.UNSIGNED_BYTE;
+            }
+            else if (typeof(T) == typeof(ushort))
+            {
+                return glComponentType.UNSIGNED_SHORT;
+            }
             else if (typeof(T) == typeof(uint))
             {
                 return glComponentType.UNSIGNED_INT;
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/SpanLike.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/SpanLike.cs
index 9c7cdd3e0..71ce55e5f 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/SpanLike.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/SpanLike.cs
@@ -475,10 +475,10 @@ namespace UniGLTF
             return new SpanLike<T>(bytes, Marshal.SizeOf<T>(), getset.Getter, getset.Setter);
         }
 
-        public static SpanLike<T> Create<T>(int count) where T : struct
+        public static SpanLike<T> Create<T>(int itemCount) where T : struct
         {
             var itemSize = Marshal.SizeOf<T>();
-            var array = new byte[count / itemSize];
+            var array = new byte[itemCount * itemSize];
             return Wrap<T>(new ArraySegment<byte>(array));
         }
 
diff --git a/Assets/VRM10/Runtime/Migration/MeshUpdater.cs b/Assets/VRM10/Runtime/Migration/MeshUpdater.cs
index 5fdf3fe61..34c5300da 100644
--- a/Assets/VRM10/Runtime/Migration/MeshUpdater.cs
+++ b/Assets/VRM10/Runtime/Migration/MeshUpdater.cs
@@ -76,7 +76,43 @@ namespace UniVRM10
             // update Mesh
             foreach (var (gltfMesh, mesh) in Enumerable.Zip(gltf.meshes, model.MeshGroups, (l, r) => (l, r.Meshes[0])))
             {
-                var indices = mesh.IndexBuffer.GetSpan<uint>();
+                SpanLike<uint> indices;
+                switch (mesh.IndexBuffer.Stride)
+                {
+                    case 1:
+                        {
+                            // byte
+                            var byte_indices = mesh.IndexBuffer.GetSpan<byte>();
+                            indices = SpanLike.Create<uint>(byte_indices.Length);
+                            for (int i = 0; i < byte_indices.Length; ++i)
+                            {
+                                indices[i] = byte_indices[i];
+                            }
+                            break;
+                        }
+
+                    case 2:
+                        {
+                            // ushort
+                            var ushort_indices = mesh.IndexBuffer.GetSpan<ushort>();
+                            indices = SpanLike.Create<uint>(ushort_indices.Length);
+                            for (int i = 0; i < ushort_indices.Length; ++i)
+                            {
+                                indices[i] = ushort_indices[i];
+                            }
+                            break;
+                        }
+
+                    case 4:
+                        {
+                            // uint
+                            indices = mesh.IndexBuffer.GetSpan<uint>();
+                            break;
+                        }
+
+                    default:
+                        throw new NotImplementedException();
+                }
                 var position = AddAccessor<Vector3>(mesh.VertexBuffer.Positions);
                 var normal = AddAccessor<Vector3>(mesh.VertexBuffer.Normals);
                 var uv = AddAccessor<Vector2>(mesh.VertexBuffer.TexCoords);