In one aspect of the present invention, a semiconductor device may include a semiconductor substrate; a first gate dielectric layer provided on the semiconductor substrate, the relative dielectric constant ratio of the first gate dielectric layer being no less than 8; a second gate dielectric layer provided on the semiconductor substrate, the relative dielectric constant ratio of the second gate dielectric layer being no less than 8; a first gate electrode provided on the first gate dielectric layer and made of germanide which is a metallic compound containing a metal element of a rare earth metal; and a second gate electrode provided on the second gate dielectric layer and made of silicide which is a metallic compound containing the same metal element of a rare earth metal as the germanide in the first gate electrode.