diff --git a/Assets/VRM10/Runtime/Components/Constraint/ConstraintAxes.cs b/Assets/VRM10/Runtime/Components/Constraint/ConstraintAxes.cs
index f2e1165a1..ab3fd2ce3 100644
--- a/Assets/VRM10/Runtime/Components/Constraint/ConstraintAxes.cs
+++ b/Assets/VRM10/Runtime/Components/Constraint/ConstraintAxes.cs
@@ -14,6 +14,13 @@ namespace UniVRM10
         Z = 4,
     }
 
+    [Flags]
+    public enum YawPitchMask
+    {
+        Yaw = 1,
+        Pitch = 2,
+    }
+
     public static class AxesMaskExtensions
     {
         public static Vector3 Freeze(this AxisMask mask, Vector3 src)
diff --git a/Assets/VRM10/Runtime/Components/Constraint/VRM10AimConstraint.cs b/Assets/VRM10/Runtime/Components/Constraint/VRM10AimConstraint.cs
index 9acb759cf..9c7874d1a 100644
--- a/Assets/VRM10/Runtime/Components/Constraint/VRM10AimConstraint.cs
+++ b/Assets/VRM10/Runtime/Components/Constraint/VRM10AimConstraint.cs
@@ -8,6 +8,18 @@ namespace UniVRM10
     [DisallowMultipleComponent]
     public class VRM10AimConstraint : VRM10Constraint
     {
+        /// <summary>
+        /// Yaw(Y), Pitch(X) の２軸だけ
+        /// </summary>
+        [SerializeField]
+        [EnumFlags]
+        YawPitchMask m_freezeAxes = default;
+        public YawPitchMask FreezeAxes
+        {
+            get => m_freezeAxes;
+            set => m_freezeAxes = value;
+        }
+
         [Header("Source")]
         [SerializeField]
         Transform m_source = default;
@@ -21,6 +33,10 @@ namespace UniVRM10
         [SerializeField]
         ObjectSpace m_destinationCoordinate = default;
 
+        /// <summary>
+        /// シリアライズは、Aim と Up で記録。
+        /// UniVRM の Editor では Aim と Up が直交しないことを許可しない。
+        /// </summary>
         [SerializeField]
         public Quaternion DestinationOffset = Quaternion.identity;
 
@@ -59,6 +75,13 @@ namespace UniVRM10
             var m = new Matrix4x4(xAxis, yAxis, zAxis, new Vector4(0, 0, 0, 1));
             var parent = TR.FromParent(transform);
             m_delta = Quaternion.Inverse(parent.Rotation * m_src.LocalInitial.Rotation * DestinationOffset) * m.rotation;
+
+            var (yaw, pitch) = Matrix4x4.Rotate(Quaternion.Inverse(m_delta)).CalcYawPitch(Vector3.forward);
+            if (m_freezeAxes.HasFlag(YawPitchMask.Yaw)) yaw = 0;
+            if (m_freezeAxes.HasFlag(YawPitchMask.Pitch)) pitch = 0;
+
+            m_delta = Quaternion.Euler(pitch, yaw, 0);
+
             transform.rotation = parent.Rotation * m_src.LocalInitial.Rotation * Delta;
         }
     }