diff --git a/CMakeLists.txt b/CMakeLists.txt
index f7c6514..0719c97 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,7 +56,7 @@ if(DOWNLOAD_SOURCE)
 		message("download xbyak/" ${file})
 	endforeach()
 
-	set(CYBOZULIB_TAG release20180509)
+	set(CYBOZULIB_TAG release20180528)
 	set(CYBOZULIB_FILES atoi.hpp bit_operation.hpp endian.hpp hash.hpp itoa.hpp random_generator.hpp unordered_map.hpp benchmark.hpp crypto.hpp exception.hpp inttype.hpp option.hpp test.hpp xorshift.hpp link_mpir.hpp link_libeay32.hpp link_ssleay32.hpp critical_section.hpp mutex.hpp serializer.hpp stream.hpp)
 	foreach(file IN ITEMS ${CYBOZULIB_FILES})
 		file(DOWNLOAD https://raw.githubusercontent.com/herumi/cybozulib/${CYBOZULIB_TAG}/include/cybozu/${file} ${mcl_SOURCE_DIR}/include/cybozu/${file})