diff --git a/src/terminal/parser.cc b/src/terminal/parser.cc
index 6dc38e8..b00547b 100644
--- a/src/terminal/parser.cc
+++ b/src/terminal/parser.cc
@@ -58,7 +58,7 @@ std::list<Parser::Action *> Parser::Parser::input( wchar_t ch )
 Parser::UTF8Parser::UTF8Parser()
   : parser(), buf_len( 0 )
 {
-  assert( BUF_SIZE >= MB_CUR_MAX );
+  assert( BUF_SIZE >= (size_t)MB_CUR_MAX );
 }
 
 std::list<Parser::Action *> Parser::UTF8Parser::input( char c )