diff --git a/src/character.c b/src/character.c
index b9a5d913e04..e72fdc0c4bd 100644
--- a/src/character.c
+++ b/src/character.c
@@ -395,7 +395,7 @@ lisp_string_width (Lisp_Object string, ptrdiff_t from, ptrdiff_t to,
 		{
 		  Lisp_Object font_info = Ffont_info (default_font, Qnil);
 		  font_width = XFIXNUM (AREF (font_info, 11));
-		  if (font_info <= 0)
+		  if (font_width <= 0)
 		    font_width = XFIXNUM (AREF (font_info, 10));
 		}
 	    }