A semiconductor device is disclosed, which comprises a silicon substrate, a complementary MISFET circuit, an insulation film formed on the silicon substrate, a first contact hole formed in the insulation film, a first metal silicide layer formed on the bottom of the first contact hole, the first metal silicide layer being provided by a reaction of the n-channel impurity diffused region of the n-channel MISFET with a first metal, a second contact hole formed in the insulation film, a second metal silicide layer formed on the bottom of the second contact hole, the second metal silicide layer being provided by a reaction of the p-channel impurity diffused region of the p-channel MISFET with a second metal, and a work function of the second metal silicide layer being higher than that of the first metal silicide layer.