diff --git a/mrbgems/mruby-sprintf/src/sprintf.c b/mrbgems/mruby-sprintf/src/sprintf.c
index 201e836cc..7b8201736 100644
--- a/mrbgems/mruby-sprintf/src/sprintf.c
+++ b/mrbgems/mruby-sprintf/src/sprintf.c
@@ -958,6 +958,7 @@ retry:
 
         if (!(flags&FMINUS) && width > 0) {
           FILL(' ', width);
+          width = 0;
         }
 
         if (sc) PUSH(&sc, 1);