diff --git a/array.c b/array.c
index 7989adeada..44a0300efd 100644
--- a/array.c
+++ b/array.c
@@ -4545,7 +4545,7 @@ rb_ary_diff(VALUE ary1, VALUE ary2)
 
 /*
  *  call-seq:
- *     ary.difference(other_ary1, other_ary2, ...)   -> ary
+ *     ary.difference(other_ary1, other_ary2, ...)   -> new_ary
  *
  *  Array Difference
  *