diff --git a/third-party/Makefile.am b/third-party/Makefile.am
index 6e9bcf27..c1955eea 100644
--- a/third-party/Makefile.am
+++ b/third-party/Makefile.am
@@ -55,7 +55,9 @@ mruby:
 all-local: mruby
 
 clean-local:
-	-rm -rf "${abs_builddir}/mruby/build"
+	MRUBY_CONFIG="${srcdir}/build_config.rb" \
+	BUILD_DIR="${abs_builddir}/mruby/build" \
+	"${srcdir}/mruby/minirake" -f "${srcdir}/mruby/Rakefile" clean
 
 endif # HAVE_MRUBY