diff --git a/include/mcl/ec.hpp b/include/mcl/ec.hpp
index b598db6..195394d 100644
--- a/include/mcl/ec.hpp
+++ b/include/mcl/ec.hpp
@@ -1491,6 +1491,7 @@ void initCurve(int curveType, Ec *P = 0, mcl::fp::Mode mode = fp::FP_AUTO, mcl::
 
 } // mcl
 
+#ifndef CYBOZU_DONT_USE_EXCEPTION
 #ifdef CYBOZU_USE_BOOST
 namespace mcl {
 template<class Fp>
@@ -1517,6 +1518,7 @@ struct hash<mcl::EcT<Fp> > {
 
 CYBOZU_NAMESPACE_TR1_END } // std
 #endif
+#endif
 
 #ifdef _MSC_VER
 	#pragma warning(pop)
diff --git a/include/mcl/fp.hpp b/include/mcl/fp.hpp
index 62d592f..a1f4b2c 100644
--- a/include/mcl/fp.hpp
+++ b/include/mcl/fp.hpp
@@ -688,6 +688,7 @@ template<class tag, size_t maxBitSize> void (*FpT<tag, maxBitSize>::sqr)(FpT& y,
 
 } // mcl
 
+#ifndef CYBOZU_DONT_USE_EXCEPTION
 #ifdef CYBOZU_USE_BOOST
 namespace mcl {
 
@@ -711,6 +712,7 @@ struct hash<mcl::FpT<tag, maxBitSize> > {
 
 CYBOZU_NAMESPACE_TR1_END } // std::tr1
 #endif
+#endif
 
 #ifdef _MSC_VER
 	#pragma warning(pop)