diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 9f71f46707..d2699caca8 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -407,7 +407,7 @@ VALUE rb_block_lambda(void);
 VALUE rb_proc_new(VALUE (*)(ANYARGS/* VALUE yieldarg[, VALUE procarg] */), VALUE);
 VALUE rb_obj_is_proc(VALUE);
 VALUE rb_proc_call(VALUE, VALUE);
-VALUE rb_proc_call_with_block(VALUE, int argc, VALUE *argv, VALUE);
+VALUE rb_proc_call_with_block(VALUE, int argc, const VALUE *argv, VALUE);
 int rb_proc_arity(VALUE);
 VALUE rb_proc_lambda_p(VALUE);
 VALUE rb_binding_new(void);
diff --git a/proc.c b/proc.c
index a27a66c0f5..d7395df72b 100644
--- a/proc.c
+++ b/proc.c
@@ -601,7 +601,7 @@ rb_proc_call(VALUE self, VALUE args)
 }
 
 VALUE
-rb_proc_call_with_block(VALUE self, int argc, VALUE *argv, VALUE pass_procval)
+rb_proc_call_with_block(VALUE self, int argc, const VALUE *argv, VALUE pass_procval)
 {
     VALUE vret;
     rb_proc_t *proc;