diff --git a/Runtime/Utility/Utility.Http.cs b/Runtime/Utility/Utility.Http.cs
index 8f41242..d6f3c61 100644
--- a/Runtime/Utility/Utility.Http.cs
+++ b/Runtime/Utility/Utility.Http.cs
@@ -27,7 +27,7 @@ namespace AlicizaX
             public static async UniTask<string> PostJson(string url, object jsonData, float timeout = 5f)
             {
                 using var cts = CreateTimeoutTokenSource(timeout);
-                var json = JsonUtility.ToJson(jsonData);
+                var json = Utility.Json.ToJson(jsonData);
                 using var request = CreateJsonPostRequest(url, json);
                 return await SendRequest(request, cts.Token);
             }