diff --git a/websocket-sharp/Net/ChunkStream.cs b/websocket-sharp/Net/ChunkStream.cs
index 7da45e3f..29bddabf 100644
--- a/websocket-sharp/Net/ChunkStream.cs
+++ b/websocket-sharp/Net/ChunkStream.cs
@@ -224,9 +224,6 @@ namespace WebSocketSharp.Net
         var b = buffer[offset++];
         _saved.Append ((char) b);
 
-        if (_saved.Length > 4196)
-          throwProtocolViolation ("The trailer is too long.");
-
         if (_trailerState == 1 || _trailerState == 3) { // CR or CR LF CR
           if (b != 10)
             throwProtocolViolation ("LF is expected.");
@@ -248,6 +245,9 @@ namespace WebSocketSharp.Net
         _trailerState = 0;
       }
 
+      if (_saved.Length > 4196)
+        throwProtocolViolation ("The trailer is too long.");
+
       if (_trailerState < 4)
         return InputChunkState.Trailer;