diff --git a/Makefile b/Makefile
index 6fee509..a8fe1d0 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,7 @@ test-compile-r7rs: tmp/test/libtest.o tmp/test/libtest.so tmp/test/libtest.a
 
 test-compile-r7rs-docker:
 	docker build --build-arg COMPILE_R7RS=${COMPILE_R7RS} --tag=r7rs-pffi-test-${COMPILE_R7RS} -f Dockerfile.test .
-	docker run -v "${PWD}":/workdir -w /workdir -t r7rs-pffi-test-${COMPILE_R7RS} sh -c "make COMPILE_R7RS=${COMPILE_R7RS} TESTNAME=${TESTNAME} test-compile-r7rs"
+	docker run -v "${PWD}:/workdir" -w /workdir -t r7rs-pffi-test-${COMPILE_R7RS} sh -c "make COMPILE_R7RS=${COMPILE_R7RS} TESTNAME=${TESTNAME} test-compile-r7rs"
 
 tmp/test/libtest.o: tests/c-src/libtest.c
 	mkdir -p tmp/test