diff --git a/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterEditorGUI.cs b/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterEditorGUI.cs
index 517016853..74f59f87c 100644
--- a/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterEditorGUI.cs
+++ b/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterEditorGUI.cs
@@ -45,9 +45,13 @@ namespace UniVRM10
             if (expressions?.Preset?.LookDown != null) yield return ExpressionKey.LookDown.SubAssetKey;
             if (expressions?.Preset?.LookLeft != null) yield return ExpressionKey.LookLeft.SubAssetKey;
             if (expressions?.Preset?.LookRight != null) yield return ExpressionKey.LookRight.SubAssetKey;
-            foreach (var kv in expressions.Custom)
+
+            if (expressions.Custom != null)
             {
-                yield return ExpressionKey.CreateCustom(kv.Key).SubAssetKey;
+                foreach (var kv in expressions.Custom)
+                {
+                    yield return ExpressionKey.CreateCustom(kv.Key).SubAssetKey;
+                }
             }
         }
 
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
index 351022032..6275035bc 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -377,13 +377,16 @@ namespace UniVRM10
                 vrm.Expression.LookDown = GetOrLoadExpression(ExpressionKey.LookDown.SubAssetKey, vrmExtension.Expressions.Preset.LookDown);
                 vrm.Expression.LookLeft = GetOrLoadExpression(ExpressionKey.LookLeft.SubAssetKey, vrmExtension.Expressions.Preset.LookLeft);
                 vrm.Expression.LookRight = GetOrLoadExpression(ExpressionKey.LookRight.SubAssetKey, vrmExtension.Expressions.Preset.LookRight);
-                foreach (var (name, expression) in vrmExtension.Expressions.Custom)
+                if (vrmExtension.Expressions.Custom != null)
                 {
-                    var key = ExpressionKey.CreateCustom(name);
-                    var clip = GetOrLoadExpression(key.SubAssetKey, expression);
-                    if (clip != null)
+                    foreach (var (name, expression) in vrmExtension.Expressions.Custom)
                     {
-                        vrm.Expression.AddClip(clip);
+                        var key = ExpressionKey.CreateCustom(name);
+                        var clip = GetOrLoadExpression(key.SubAssetKey, expression);
+                        if (clip != null)
+                        {
+                            vrm.Expression.AddClip(clip);
+                        }
                     }
                 }
             }