diff --git a/src/variable.c b/src/variable.c
index 32416da4e..ab3bea327 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -268,8 +268,10 @@ mrb_gc_mark_gv(mrb_state *mrb)
 void
 mrb_gc_free_gv(mrb_state *mrb)
 {
-  if (mrb->globals)
+  if (mrb->globals) {
     iv_free(mrb, mrb->globals);
+    mrb->globals = NULL;
+  }
 }
 
 void