diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 6052484b..2c06a8ab 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -302,6 +302,13 @@ namespace WebSocketSharp
              : null;
     }
 
+    internal static string CheckIfValidWaitTime (this TimeSpan time)
+    {
+      return time <= TimeSpan.Zero
+             ? "A wait time is zero or less."
+             : null;
+    }
+
     internal static void Close (this HttpListenerResponse response, HttpStatusCode code)
     {
       response.StatusCode = (int) code;
diff --git a/websocket-sharp/Server/WebSocketServer.cs b/websocket-sharp/Server/WebSocketServer.cs
index 6d3d83e5..73bcfe1c 100644
--- a/websocket-sharp/Server/WebSocketServer.cs
+++ b/websocket-sharp/Server/WebSocketServer.cs
@@ -481,6 +481,29 @@ namespace WebSocketSharp.Server
       }
     }
 
+    /// <summary>
+    /// Gets or sets the wait time for the response to the WebSocket Ping or Close.
+    /// </summary>
+    /// <value>
+    /// A <see cref="TimeSpan"/> that represents the wait time. The default value is
+    /// the same as 1 second.
+    /// </value>
+    public TimeSpan WaitTime {
+      get {
+        return _services.WaitTime;
+      }
+
+      set {
+        var msg = _state.CheckIfStartable () ?? value.CheckIfValidWaitTime ();
+        if (msg != null) {
+          _logger.Error (msg);
+          return;
+        }
+
+        _services.WaitTime = value;
+      }
+    }
+
     /// <summary>
     /// Gets the access to the WebSocket services provided by the server.
     /// </summary>
diff --git a/websocket-sharp/Server/WebSocketServiceHost.cs b/websocket-sharp/Server/WebSocketServiceHost.cs
index 21407902..8034e841 100644
--- a/websocket-sharp/Server/WebSocketServiceHost.cs
+++ b/websocket-sharp/Server/WebSocketServiceHost.cs
@@ -67,16 +67,6 @@ namespace WebSocketSharp.Server
       }
     }
 
-    internal TimeSpan WaitTime {
-      get {
-        return Sessions.WaitTime;
-      }
-
-      set {
-        Sessions.WaitTime = value;
-      }
-    }
-
     #endregion
 
     #region Public Properties
@@ -115,6 +105,15 @@ namespace WebSocketSharp.Server
     /// </value>
     public abstract Type Type { get; }
 
+    /// <summary>
+    /// Gets or sets the wait time for the response to the WebSocket Ping or Close.
+    /// </summary>
+    /// <value>
+    /// A <see cref="TimeSpan"/> that represents the wait time. The default value is
+    /// the same as 1 second.
+    /// </value>
+    public abstract TimeSpan WaitTime { get; set; }
+
     #endregion
 
     #region Internal Methods
@@ -162,6 +161,7 @@ namespace WebSocketSharp.Server
     #region Private Fields
 
     private Func<TBehavior>         _initializer;
+    private Logger                  _logger;
     private string                  _path;
     private WebSocketSessionManager _sessions;
 
@@ -173,6 +173,7 @@ namespace WebSocketSharp.Server
     {
       _path = path;
       _initializer = initializer;
+      _logger = logger;
       _sessions = new WebSocketSessionManager (logger);
     }
 
@@ -208,6 +209,22 @@ namespace WebSocketSharp.Server
       }
     }
 
+    public override TimeSpan WaitTime {
+      get {
+        return _sessions.WaitTime;
+      }
+
+      set {
+        var msg = _sessions.State.CheckIfStartable () ?? value.CheckIfValidWaitTime ();
+        if (msg != null) {
+          _logger.Error (msg);
+          return;
+        }
+
+        _sessions.WaitTime = value;
+      }
+    }
+
     #endregion
 
     #region Protected Methods
diff --git a/websocket-sharp/Server/WebSocketServiceManager.cs b/websocket-sharp/Server/WebSocketServiceManager.cs
index 949d9d69..1f4e541e 100644
--- a/websocket-sharp/Server/WebSocketServiceManager.cs
+++ b/websocket-sharp/Server/WebSocketServiceManager.cs
@@ -73,27 +73,6 @@ namespace WebSocketSharp.Server
 
     #endregion
 
-    #region Internal Properties
-
-    internal TimeSpan WaitTime {
-      get {
-        return _waitTime;
-      }
-
-      set {
-        lock (_sync) {
-          if (value == _waitTime)
-            return;
-
-          _waitTime = value;
-          foreach (var host in _hosts.Values)
-            host.WaitTime = value;
-        }
-      }
-    }
-
-    #endregion
-
     #region Public Properties
 
     /// <summary>
@@ -201,6 +180,29 @@ namespace WebSocketSharp.Server
       }
     }
 
+    /// <summary>
+    /// Gets the wait time for the response to the WebSocket Ping or Close.
+    /// </summary>
+    /// <value>
+    /// A <see cref="TimeSpan"/> that represents the wait time.
+    /// </value>
+    public TimeSpan WaitTime {
+      get {
+        return _waitTime;
+      }
+
+      internal set {
+        lock (_sync) {
+          if (value == _waitTime)
+            return;
+
+          _waitTime = value;
+          foreach (var host in _hosts.Values)
+            host.WaitTime = value;
+        }
+      }
+    }
+
     #endregion
 
     #region Private Methods
diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index 021857fe..7ebdd17f 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -86,21 +86,6 @@ namespace WebSocketSharp.Server
       }
     }
 
-    internal TimeSpan WaitTime {
-      get {
-        return _waitTime;
-      }
-
-      set {
-        if (value == _waitTime)
-          return;
-
-        _waitTime = value;
-        foreach (var session in Sessions)
-          session.Context.WebSocket.WaitTime = value;
-      }
-    }
-
     #endregion
 
     #region Public Properties
@@ -224,6 +209,27 @@ namespace WebSocketSharp.Server
       }
     }
 
+    /// <summary>
+    /// Gets the wait time for the response to the WebSocket Ping or Close.
+    /// </summary>
+    /// <value>
+    /// A <see cref="TimeSpan"/> that represents the wait time.
+    /// </value>
+    public TimeSpan WaitTime {
+      get {
+        return _waitTime;
+      }
+
+      internal set {
+        if (value == _waitTime)
+          return;
+
+        _waitTime = value;
+        foreach (var session in Sessions)
+          session.Context.WebSocket.WaitTime = value;
+      }
+    }
+
     #endregion
 
     #region Private Methods