A semiconductor device includes an n-type MIS (Metal Insulator Semiconductor) transistor and a p-type MIS transistor. The n-type MIS transistor includes a first gate insulating film, a first fully silicided (FUSI) gate electrode formed on the first gate insulating film and made of a first metal silicide film, and a first sidewall insulating film. The p-type MIS transistor includes a second gate insulating film, a second fully silicided (FUSI) gate electrode formed on the second gate insulating film and made of a second metal silicide film, and a second sidewall insulating film. A top surface of the first FUSI gate electrode is located lower than a top surface of the second FUSI gate electrode.