diff --git a/include/mcl/ec.hpp b/include/mcl/ec.hpp
index 1ab508a..bbaabd7 100644
--- a/include/mcl/ec.hpp
+++ b/include/mcl/ec.hpp
@@ -1009,6 +1009,20 @@ public:
 	{
 		mulArrayBase(z, x, gmp::getUnit(y), gmp::getUnitSize(y), y < 0, constTime);
 	}
+	/*
+		z = sum_{i=0}^{n-1} xVec[i] * yVec[i]
+	*/
+	template<class tag, size_t maxBitSize, template<class _tag, size_t _maxBitSize>class FpT>
+	static inline void mulVec(EcT& z, const EcT *xVec, const FpT<tag, maxBitSize> *yVec, size_t n)
+	{
+		EcT r, t;
+		r.clear();
+		for (size_t i = 0; i < n; i++) {
+			mul(t, xVec[i], yVec[i]);
+			r += t;
+		}
+		z = r;
+	}
 #ifndef CYBOZU_DONT_USE_EXCEPTION
 	static inline void init(const std::string& astr, const std::string& bstr, int mode = ec::Jacobi)
 	{
diff --git a/test/bls12_test.cpp b/test/bls12_test.cpp
index 5af112f..c86fed2 100644
--- a/test/bls12_test.cpp
+++ b/test/bls12_test.cpp
@@ -6,6 +6,7 @@ cybozu::CpuClock clk;
 #include <mcl/bls12_381.hpp>
 #include <cybozu/option.hpp>
 #include <cybozu/xorshift.hpp>
+#include "common_test.hpp"
 
 #if defined(__EMSCRIPTEN__) && !defined(MCL_AVOID_EXCEPTION_TEST)
 	#define MCL_AVOID_EXCEPTION_TEST
@@ -383,6 +384,7 @@ CYBOZU_TEST_AUTO(naive)
 		testPairing(P, Q, ts.e);
 		testPrecomputed(P, Q);
 		testMillerLoop2(P, Q);
+		testCommon();
 		testBench(P, Q);
 	}
 	int count = (int)clk.getCount();
diff --git a/test/bn384_test.cpp b/test/bn384_test.cpp
index b5674a9..a8c7cdb 100644
--- a/test/bn384_test.cpp
+++ b/test/bn384_test.cpp
@@ -5,6 +5,7 @@
 #include <cybozu/xorshift.hpp>
 #include <mcl/bn384.hpp>
 #include <mcl/bn.hpp>
+#include "common_test.hpp"
 
 using namespace mcl::bn384;
 
@@ -39,6 +40,7 @@ void testCurve(const mcl::CurveParam& cp)
 	pairing(e2, aP, bQ);
 	GT::pow(e1, e1, a * b);
 	CYBOZU_TEST_EQUAL(e1, e2);
+	testCommon();
 	testBench(P, Q);
 	testSquareRoot();
 	testLagrange();
diff --git a/test/bn512_test.cpp b/test/bn512_test.cpp
index 905bfd3..db2aff1 100644
--- a/test/bn512_test.cpp
+++ b/test/bn512_test.cpp
@@ -5,6 +5,7 @@
 #include <cybozu/xorshift.hpp>
 #include <mcl/bn512.hpp>
 #include <mcl/bn.hpp>
+#include "common_test.hpp"
 
 using namespace mcl::bn512;
 
@@ -33,6 +34,7 @@ void testCurve(const mcl::CurveParam& cp)
 	pairing(e2, aP, bQ);
 	GT::pow(e1, e1, a * b);
 	CYBOZU_TEST_EQUAL(e1, e2);
+	testCommon();
 	testBench(P, Q);
 	testSquareRoot();
 	testLagrange();
diff --git a/test/bn_test.cpp b/test/bn_test.cpp
index b66cad8..a2557a3 100644
--- a/test/bn_test.cpp
+++ b/test/bn_test.cpp
@@ -6,6 +6,7 @@ cybozu::CpuClock clk;
 #include <mcl/bn256.hpp>
 #include <cybozu/option.hpp>
 #include <cybozu/xorshift.hpp>
+#include "common_test.hpp"
 
 #if defined(__EMSCRIPTEN__) && !defined(MCL_AVOID_EXCEPTION_TEST)
 	#define MCL_AVOID_EXCEPTION_TEST
@@ -401,6 +402,7 @@ CYBOZU_TEST_AUTO(naive)
 		testPrecomputed(P, Q);
 		testMillerLoop2(P, Q);
 		testMillerLoopVec();
+		testCommon();
 		testBench(P, Q);
 		benchAddDblG1();
 		benchAddDblG2();
diff --git a/test/common_test.hpp b/test/common_test.hpp
new file mode 100644
index 0000000..e29fd1f
--- /dev/null
+++ b/test/common_test.hpp
@@ -0,0 +1,25 @@
+void testMulVec()
+{
+	using namespace mcl::bn;
+	const size_t n = 5;
+	G1 xVec[n];
+	Fr yVec[n];
+	G1 ok;
+	ok.clear();
+	char c = 'a';
+	for (size_t i = 0; i < n; i++) {
+		hashAndMapToG1(xVec[i], &c, 1);
+		yVec[i].setByCSPRNG();
+		G1 t;
+		G1::mul(t, xVec[i], yVec[i]);
+		ok += t;
+	}
+	G1 z;
+	G1::mulVec(z, xVec, yVec, n);
+	CYBOZU_TEST_EQUAL(z, ok);
+}
+
+void testCommon()
+{
+	testMulVec();
+}