diff --git a/test/bench.hpp b/test/bench.hpp
index 660aa13..69aff50 100644
--- a/test/bench.hpp
+++ b/test/bench.hpp
@@ -3,6 +3,10 @@
 void benchAddDblG1()
 {
 	puts("benchAddDblG1");
+#ifndef NDEBUG
+	puts("skip in debug");
+	return;
+#endif
 	const int C = 100000;
 	G1 P1, P2, P3;
 	hashAndMapToG1(P1, "a");
@@ -29,6 +33,10 @@ void benchAddDblG1()
 void benchAddDblG2()
 {
 	puts("benchAddDblG2");
+#ifndef NDEBUG
+	puts("skip in debug");
+	return;
+#endif
 	const int C = 100000;
 	G2 P1, P2, P3;
 	hashAndMapToG2(P1, "a");
@@ -61,6 +69,10 @@ void invAdd(T& out, const T& x, const T& y)
 
 void testBench(const G1& P, const G2& Q)
 {
+#ifndef NDEBUG
+	puts("testBench skip in debug");
+	return;
+#endif
 	G1 Pa;
 	G2 Qa;
 	Fp12 e1, e2;
diff --git a/test/bls12_test.cpp b/test/bls12_test.cpp
index ec4204c..e6c691a 100644
--- a/test/bls12_test.cpp
+++ b/test/bls12_test.cpp
@@ -431,6 +431,10 @@ const char *e1Str =
 	finalExp(e2, e0);
 //	finalExpC(e2, e0);
 	CYBOZU_TEST_EQUAL(e1, e2);
+#ifndef NDEBUG
+	puts("skip bench of finalExp in debug");
+	return;
+#endif
 	CYBOZU_BENCH_C("finalExp", 100, finalExp, e2, e0);
 }
 
@@ -685,6 +689,10 @@ void testCurve(const mcl::CurveParam& cp)
 }
 CYBOZU_TEST_AUTO(multi)
 {
+#ifndef NDEBUG
+	puts("skip multi in debug");
+	return;
+#endif
 	G1 P;
 	G2 Q;
 	int i;
@@ -722,6 +730,10 @@ CYBOZU_TEST_AUTO(deserialize)
 	size_t n2 = Q.serialize(buf2, sizeof(buf2));
 	CYBOZU_TEST_ASSERT(n2 > 0);
 	CYBOZU_TEST_EQUAL(Q.deserialize(buf2, n2), n2);
+#ifndef NDEBUG
+	puts("skip bench in debug");
+	return;
+#endif
 	for (int i = 0; i < 2; i++) {
 		bool doVerify = i == 0;
 		printf("verifyOrder(%d)\n", doVerify);
diff --git a/test/fp_tower_test.cpp b/test/fp_tower_test.cpp
index 5dd3a70..3a45618 100644
--- a/test/fp_tower_test.cpp
+++ b/test/fp_tower_test.cpp
@@ -378,6 +378,10 @@ void testIo()
 void benchFp2()
 {
 	puts(__FUNCTION__);
+#ifndef NDEBUG
+	puts("skip bench in debug");
+	return;
+#endif
 	Fp2 x, y;
 	x.a.setStr("4");
 	x.b.setStr("464652165165");
diff --git a/test/paillier_test.cpp b/test/paillier_test.cpp
index 31d2b26..7bb6e99 100644
--- a/test/paillier_test.cpp
+++ b/test/paillier_test.cpp
@@ -5,7 +5,11 @@ CYBOZU_TEST_AUTO(paillier)
 {
 	using namespace mcl::paillier;
 	SecretKey sec;
+#ifndef NDEBUG
+	sec.init(512);
+#else
 	sec.init(2048);
+#endif
 	PublicKey pub;
 	sec.getPublicKey(pub);
 	mpz_class m1("12342340928409"), m2("23049820498204");
diff --git a/test/she_test.cpp b/test/she_test.cpp
index 9ef51c7..f49f29f 100644
--- a/test/she_test.cpp
+++ b/test/she_test.cpp
@@ -43,6 +43,9 @@ double clk2msec(const cybozu::CpuClock& clk, int n)
 
 CYBOZU_TEST_AUTO(bench2)
 {
+#ifndef NDEBUG
+	puts("skip bench2 in debug");
+#endif
 	puts("msec");
 	setTryNum(1 << 16);
 	useDecG1ViaGT(true);
@@ -571,7 +574,7 @@ CYBOZU_TEST_AUTO(io)
 	}
 }
 
-#ifndef PAPER
+#if !defined(PAPER) && defined(NDEBUG)
 CYBOZU_TEST_AUTO(bench)
 {
 	const SecretKey& sec = g_sec;