diff --git a/utsushi/utsushi/functional.hpp b/utsushi/utsushi/functional.hpp
index 1e84119..75fe20e 100644
--- a/utsushi/utsushi/functional.hpp
+++ b/utsushi/utsushi/functional.hpp
@@ -58,6 +58,7 @@ using NAMESPACE::bind;
 using NAMESPACE::function;
 using NAMESPACE::ref;
 using NAMESPACE::reference_wrapper;
+using namespace NAMESPACE::placeholders;
 
 }       // namespace utsushi