diff --git a/Packages/VRM10/Runtime/IO/Vrm10Exporter.cs b/Packages/VRM10/Runtime/IO/Vrm10Exporter.cs
index fc6724f5d..c9078701f 100644
--- a/Packages/VRM10/Runtime/IO/Vrm10Exporter.cs
+++ b/Packages/VRM10/Runtime/IO/Vrm10Exporter.cs
@@ -14,6 +14,7 @@ namespace UniVRM10
         public const string SPRINGBONE_EXTENDED_COLLIDER_SPEC_VERSION = "1.0";
         public const string NODE_CONSTRAINT_SPEC_VERSION = "1.0";
         public const string MTOON_SPEC_VERSION = "1.0";
+        public const string VRMC_springBone_limit_SPEC_VERSION = "1.0-draft";
 
         public const string LICENSE_URL_JA = "https://vrm.dev/licenses/1.0/";
         public const string LICENSE_URL_EN = "https://vrm.dev/licenses/1.0/en/";
@@ -457,6 +458,7 @@ namespace UniVRM10
                     {
                         var limit = new UniGLTF.Extensions.VRMC_springBone_limit.VRMC_springBone_limit
                         {
+                            SpecVersion = VRMC_springBone_limit_SPEC_VERSION,
                             Limit = new UniGLTF.Extensions.VRMC_springBone_limit.Limit
                             {
                                 Cone = new UniGLTF.Extensions.VRMC_springBone_limit.ConeLimit
diff --git a/Packages/VRM10/Runtime/IO/Vrm10Importer.cs b/Packages/VRM10/Runtime/IO/Vrm10Importer.cs
index 4c1c9a5d5..6265a326b 100644
--- a/Packages/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Packages/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -685,7 +685,7 @@ namespace UniVRM10
         private static bool VRMC_springBone_limit_Validate(Transform node, VRMC_springBone_limit extensionSpringBoneLimit)
         {
             var validate = true;
-            if (extensionSpringBoneLimit.SpecVersion != "1.0-draft")
+            if (extensionSpringBoneLimit.SpecVersion != Vrm10Exporter.VRMC_springBone_limit_SPEC_VERSION)
             {
                 UniGLTFLogger.Warning($"Unknown VRMC_springBone_limit specVersion: {extensionSpringBoneLimit.SpecVersion}");
             }