diff --git a/websocket-sharp/Server/WebSocketServiceManager.cs b/websocket-sharp/Server/WebSocketServiceManager.cs
index 42f1e3e1..9b62ad79 100644
--- a/websocket-sharp/Server/WebSocketServiceManager.cs
+++ b/websocket-sharp/Server/WebSocketServiceManager.cs
@@ -767,7 +767,7 @@ namespace WebSocketSharp.Server
     ///   <para>
     ///   It represents a collection of pairs of a service path and another
     ///   collection of pairs of a session ID and a value indicating whether
-    ///   a pong has been received from its client within a time.
+    ///   a pong has been received from the client within a time.
     ///   </para>
     /// </returns>
     /// <exception cref="InvalidOperationException">