diff --git a/Makefile b/Makefile
index ed4aae79..5cfe946f 100644
--- a/Makefile
+++ b/Makefile
@@ -149,6 +149,7 @@ single_test:
 	@echo "********************" Error
 	@tail -n 30 pp/*/error.txt
 	@rm -f tests/input_samples/bom.ini
+	@rm .coverage.kotori.*
 
 single_tests:
 	rm -rf pp