A semiconductor device includes: a first gate insulating film on a first region of a semiconductor substrate; a first gate electrode on the first gate insulating film; a second gate insulating film on a second region of the semiconductor substrate; and a second gate electrode on the second gate insulating film. The first gate insulating film includes a first insulating film composed of a first material containing a first metal, and the second gate insulating film includes a second insulating film composed of the first material and a second material containing a second metal.