diff --git a/parse.y b/parse.y
index ced7a8c86d..150fe795f8 100644
--- a/parse.y
+++ b/parse.y
@@ -5155,6 +5155,7 @@ lambda		: tLAMBDA[lpar]
                             nd_set_line(RNODE_LAMBDA($$)->nd_body, @body.end_pos.lineno);
                             nd_set_line($$, @args.end_pos.lineno);
                             nd_set_first_loc($$, @1.beg_pos);
+                            xfree($body);
                         }
                     /*% ripper: lambda!($:args, $:body) %*/
                         numparam_pop(p, $numparam);
diff --git a/test/ripper/test_ripper.rb b/test/ripper/test_ripper.rb
index 070023b536..2b3421d827 100644
--- a/test/ripper/test_ripper.rb
+++ b/test/ripper/test_ripper.rb
@@ -187,6 +187,13 @@ end
         Ripper.parse("-> {")
       end
     end;
+
+    # [Bug #21004]
+    assert_no_memory_leak(%w(-rripper), "", <<~RUBY, rss: true)
+      1_000_000.times do
+        Ripper.parse("-> do it end")
+      end
+    RUBY
   end
 
   def test_sexp_no_memory_leak