diff --git a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
index ac9b744ff..585478a26 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
@@ -50,6 +50,20 @@ namespace UniVRM10
         [SerializeField]
         public VRM10ObjectLookAt.LookAtTargetTypes LookAtTargetType;
 
+        UniHumanoid.Humanoid m_humanoid;
+
+        public UniHumanoid.Humanoid Humanoid
+        {
+            get
+            {
+                if (m_humanoid == null)
+                {
+                    m_humanoid = GetComponent<UniHumanoid.Humanoid>();
+                }
+                return m_humanoid;
+            }
+        }
+
         Vrm10Runtime m_runtime;
 
         /// <summary>
@@ -111,5 +125,15 @@ namespace UniVRM10
                 }
             }
         }
+
+        public bool TryGetBoneTransform(HumanBodyBones bone, out Transform t)
+        {
+            t = Humanoid.GetBoneTransform(bone);
+            if (t == null)
+            {
+                return false;
+            }
+            return true;
+        }
     }
 }
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
index efaefef26..bf8aa4f41 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
@@ -27,14 +27,12 @@ namespace UniVRM10
         public Vrm10Runtime(Vrm10Instance target)
         {
             m_target = target;
-            var animator = target.GetComponent<Animator>();
-            if (animator == null)
+
+            if (!target.TryGetBoneTransform(HumanBodyBones.Head, out m_head))
             {
                 throw new Exception();
             }
-
-            m_head = animator.GetBoneTransform(HumanBodyBones.Head);
-            m_lookat = new Vrm10RuntimeLookAt(target.Vrm.LookAt, animator, m_head, target.LookAtTargetType, target.Gaze);
+            m_lookat = new Vrm10RuntimeLookAt(target.Vrm.LookAt, target.Humanoid, m_head, target.LookAtTargetType, target.Gaze);
             m_expression = new Vrm10RuntimeExpression(target, m_lookat, m_lookat.EyeDirectionApplicable);
 
             if (m_constraints == null)
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeLookAt.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeLookAt.cs
index c23e9d14b..b166efc7a 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeLookAt.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeLookAt.cs
@@ -5,7 +5,7 @@ using UnityEngine;
 
 namespace UniVRM10
 {
-    public class Vrm10RuntimeLookAt: ILookAtEyeDirectionProvider
+    public class Vrm10RuntimeLookAt : ILookAtEyeDirectionProvider
     {
         VRM10ObjectLookAt m_lookat;
 
@@ -85,13 +85,13 @@ namespace UniVRM10
             throw new NotImplementedException();
         }
 
-        internal Vrm10RuntimeLookAt(VRM10ObjectLookAt lookat, Animator animator, Transform head, VRM10ObjectLookAt.LookAtTargetTypes lookAtTargetType, Transform gaze)
+        internal Vrm10RuntimeLookAt(VRM10ObjectLookAt lookat, UniHumanoid.Humanoid humanoid, Transform head, VRM10ObjectLookAt.LookAtTargetTypes lookAtTargetType, Transform gaze)
         {
             m_lookat = lookat;
 
             m_head = head;
-            m_leftEye = animator.GetBoneTransform(HumanBodyBones.LeftEye);
-            m_rightEye = animator.GetBoneTransform(HumanBodyBones.RightEye);
+            m_leftEye = humanoid.GetBoneTransform(HumanBodyBones.LeftEye);
+            m_rightEye = humanoid.GetBoneTransform(HumanBodyBones.RightEye);
 
             var isRuntimeAsset = true;
 #if UNITY_EDITOR
@@ -122,6 +122,5 @@ namespace UniVRM10
             var (yaw, pitch) = GetLookAtYawPitch(m_head, lookAtTargetType, gaze);
             EyeDirection = new LookAtEyeDirection(yaw, pitch, 0, 0);
         }
-
     }
 }
diff --git a/Assets/VRM10/Runtime/IO/Model/ModelExporter.cs b/Assets/VRM10/Runtime/IO/Model/ModelExporter.cs
index 730db432b..899537002 100644
--- a/Assets/VRM10/Runtime/IO/Model/ModelExporter.cs
+++ b/Assets/VRM10/Runtime/IO/Model/ModelExporter.cs
@@ -45,7 +45,15 @@ namespace UniVRM10
                     var transform = humanoid.GetBoneTransform(humanBoneType);
                     if (transform != null && Nodes.TryGetValue(transform.gameObject, out VrmLib.Node node))
                     {
-                        node.HumanoidBone = (VrmLib.HumanoidBones)Enum.Parse(typeof(VrmLib.HumanoidBones), humanBoneType.ToString(), true);
+                        switch (humanBoneType)
+                        {
+                            // https://github.com/vrm-c/vrm-specification/issues/380
+                            case HumanBodyBones.LeftThumbProximal: node.HumanoidBone = VrmLib.HumanoidBones.leftThumbMetacarpal; break;
+                            case HumanBodyBones.LeftThumbIntermediate: node.HumanoidBone = VrmLib.HumanoidBones.leftThumbProximal; break;
+                            case HumanBodyBones.RightThumbProximal: node.HumanoidBone = VrmLib.HumanoidBones.rightThumbMetacarpal; break;
+                            case HumanBodyBones.RightThumbIntermediate: node.HumanoidBone = VrmLib.HumanoidBones.rightThumbProximal; break;
+                            default: node.HumanoidBone = (VrmLib.HumanoidBones)Enum.Parse(typeof(VrmLib.HumanoidBones), humanBoneType.ToString(), true); break;
+                        }
                     }
                 }
             }
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
index 234dcacd1..1fab7d277 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -722,9 +722,14 @@ namespace UniVRM10
 
         public static HumanBodyBones ToUnity(VrmLib.HumanoidBones bone)
         {
-            if (bone == VrmLib.HumanoidBones.unknown)
+            switch (bone)
             {
-                return HumanBodyBones.LastBone;
+                // https://github.com/vrm-c/vrm-specification/issues/380
+                case VrmLib.HumanoidBones.unknown: return HumanBodyBones.LastBone;
+                case VrmLib.HumanoidBones.leftThumbMetacarpal: return HumanBodyBones.LeftThumbProximal;
+                case VrmLib.HumanoidBones.leftThumbProximal: return HumanBodyBones.LeftThumbIntermediate;
+                case VrmLib.HumanoidBones.rightThumbMetacarpal: return HumanBodyBones.RightThumbProximal;
+                case VrmLib.HumanoidBones.rightThumbProximal: return HumanBodyBones.RightThumbIntermediate;
             }
             return VrmLib.EnumUtil.Cast<HumanBodyBones>(bone);
         }