diff --git a/src/codedump.c b/src/codedump.c
index 62b2fbd63..20397907e 100644
--- a/src/codedump.c
+++ b/src/codedump.c
@@ -503,7 +503,7 @@ codedump(mrb_state *mrb, const mrb_irep *irep)
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_STRCAT, B):
-      printf("STRCAT\tR%d\tR%d", a, a+1);
+      printf("STRCAT\tR%d\tR%d\t", a, a+1);
       print_lv_a(mrb, irep, a);
       break;
     CASE(OP_HASH, BB):