diff --git a/doc/nghttpx.h2r b/doc/nghttpx.h2r
index 8901ae7a..abbc4c9a 100644
--- a/doc/nghttpx.h2r
+++ b/doc/nghttpx.h2r
@@ -149,7 +149,9 @@ has to deploy key generator program to update keys frequently (e.g.,
 every 1 hour).  The example key generator tlsticketupdate.go is
 available under contrib directory in nghttp2 archive.  The memcached
 entry key is ``nghttpx:tls-ticket-key``.  The data format stored in
-memcached is the binary format described below::
+memcached is the binary format described below:
+
+.. code-block:: text
 
     +--------------+-------+----------------+
     | VERSION (4)  |LEN (2)|KEY(48 or 80) ...