diff --git a/boost/network/protocol/http/client/facade.hpp b/boost/network/protocol/http/client/facade.hpp
index 771719a93..0d175acd9 100644
--- a/boost/network/protocol/http/client/facade.hpp
+++ b/boost/network/protocol/http/client/facade.hpp
@@ -131,7 +131,7 @@ class basic_client_facade {
     } else {
       if (boost::empty(content_type_headers)) {
         typedef typename char_<Tag>::type char_type;
-        static char_type content_type[] = "x-application/octet-stream";
+        static char_type const content_type[] = "x-application/octet-stream";
         request << header("Content-Type", content_type);
       }
     }
@@ -236,7 +236,7 @@ class basic_client_facade {
     } else {
       if (boost::empty(content_type_headers)) {
         typedef typename char_<Tag>::type char_type;
-        static char_type content_type[] = "x-application/octet-stream";
+        static char_type const content_type[] = "x-application/octet-stream";
         request << header("Content-Type", content_type);
       }
     }