diff --git a/Assets/VRM/UniGLTF/Editor/Tests/UniGLTFTests.cs b/Assets/VRM/UniGLTF/Editor/Tests/UniGLTFTests.cs
index a453d0176..6eb3b37a7 100644
--- a/Assets/VRM/UniGLTF/Editor/Tests/UniGLTFTests.cs
+++ b/Assets/VRM/UniGLTF/Editor/Tests/UniGLTFTests.cs
@@ -271,7 +271,7 @@ namespace UniGLTF
             };
 
             var json = model.ToJson();
-            Assert.AreEqual(@"{""name"":""a"",""emissiveFactor"":[0.5,0.5,0.5],""doubleSided"":false}", json);
+            Assert.AreEqual(@"{""name"":""a"",""pbrMetallicRoughness"":{""baseColorFactor"":[1,1,1,1],""metallicFactor"":1,""roughnessFactor"":1},""emissiveFactor"":[0.5,0.5,0.5],""doubleSided"":false}", json);
             Debug.Log(json);
 
             var c = new JsonSchemaValidationContext("")
@@ -279,7 +279,7 @@ namespace UniGLTF
                 EnableDiagnosisForNotRequiredFields = true,
             };
             var json2 = JsonSchema.FromType<glTFMaterial>().Serialize(model, c);
-            Assert.AreEqual(@"{""name"":""a"",""emissiveFactor"":[0.5,0.5,0.5],""doubleSided"":false}", json2);
+            Assert.AreEqual(@"{""name"":""a"",""pbrMetallicRoughness"":{""baseColorFactor"":[1,1,1,1],""metallicFactor"":1,""roughnessFactor"":1},""emissiveFactor"":[0.5,0.5,0.5],""doubleSided"":false}", json2);
         }
 
         [Test]
@@ -297,7 +297,7 @@ namespace UniGLTF
                 EnableDiagnosisForNotRequiredFields = true,
             };
             var json = JsonSchema.FromType<glTFMaterial>().Serialize(model, c);
-            Assert.AreEqual(@"{""name"":""a"",""emissiveFactor"":[0.5,0.5,0.5],""alphaMode"":""MASK"",""alphaCutoff"":0.5,""doubleSided"":false}", json);
+            Assert.AreEqual(@"{""name"":""a"",""pbrMetallicRoughness"":{""baseColorFactor"":[1,1,1,1],""metallicFactor"":1,""roughnessFactor"":1},""emissiveFactor"":[0.5,0.5,0.5],""alphaMode"":""MASK"",""alphaCutoff"":0.5,""doubleSided"":false}", json);
         }
 
         [Test]
diff --git a/Assets/VRM/UniGLTF/Scripts/Format/glTFMaterial.cs b/Assets/VRM/UniGLTF/Scripts/Format/glTFMaterial.cs
index 6f6b53193..59c4f840e 100644
--- a/Assets/VRM/UniGLTF/Scripts/Format/glTFMaterial.cs
+++ b/Assets/VRM/UniGLTF/Scripts/Format/glTFMaterial.cs
@@ -147,7 +147,10 @@ namespace UniGLTF
     public class glTFMaterial : JsonSerializableBase
     {
         public string name;
-        public glTFPbrMetallicRoughness pbrMetallicRoughness;
+        public glTFPbrMetallicRoughness pbrMetallicRoughness = new glTFPbrMetallicRoughness
+        {
+            baseColorFactor = new float[] { 1.0f, 1.0f, 1.0f, 1.0f },
+        };
         public glTFMaterialNormalTextureInfo normalTexture = null;
 
         public glTFMaterialOcclusionTextureInfo occlusionTexture = null;
@@ -214,8 +217,8 @@ namespace UniGLTF
         {
             return new glTFTextureInfo[]
             {
-                pbrMetallicRoughness.baseColorTexture,
-                pbrMetallicRoughness.metallicRoughnessTexture,
+                (pbrMetallicRoughness != null)?pbrMetallicRoughness.baseColorTexture:null,
+                (pbrMetallicRoughness != null)?pbrMetallicRoughness.metallicRoughnessTexture:null,
                 normalTexture,
                 occlusionTexture,
                 emissiveTexture