diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index f27a5534..fb4b670d 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -583,17 +583,36 @@ namespace WebSocketSharp.Server
     }
 
     /// <summary>
-    /// Sends a Ping with the specified <paramref name="message"/> to every client in
-    /// the WebSocket service.
+    /// Sends a ping with the specified <paramref name="message"/> to
+    /// every client in the WebSocket service.
     /// </summary>
     /// <returns>
-    /// A <c>Dictionary&lt;string, bool&gt;</c> that contains a collection of pairs of
-    /// a session ID and a value indicating whether the manager received a Pong from
-    /// each client in a time.
+    ///   <para>
+    ///   A <c>Dictionary&lt;string, bool&gt;</c>.
+    ///   </para>
+    ///   <para>
+    ///   It represents a collection of pairs of a session ID and
+    ///   a value indicating whether a pong has been received from
+    ///   its client within a time.
+    ///   </para>
     /// </returns>
     /// <param name="message">
-    /// A <see cref="string"/> that represents the message to send.
+    ///   <para>
+    ///   A <see cref="string"/> that represents the message to send.
+    ///   </para>
+    ///   <para>
+    ///   The size must be 125 bytes or less in UTF-8.
+    ///   </para>
     /// </param>
+    /// <exception cref="InvalidOperationException">
+    /// The current state of the manager is not Start.
+    /// </exception>
+    /// <exception cref="ArgumentException">
+    /// <paramref name="message"/> could not be UTF-8-encoded.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">
+    /// The size of <paramref name="message"/> is greater than 125 bytes.
+    /// </exception>
     public Dictionary<string, bool> Broadping (string message)
     {
       if (_state != ServerState.Start) {