A first NMIS transistor includes: a first gate dielectric film over the first active region; a first gate electrode on the first gate dielectric film; a first side-wall dielectric film on side surfaces of the first gate dielectric film and the first gate electrode; a first source/drain region in the first active region outside the first side-wall dielectric film; a first silicide layer in a top-layer portion of the first source/drain region; a second side-wall dielectric film on the first silicide layer around a corner at which the side surface of the first side-wall dielectric film meets an upper surface of the first silicide layer; and a first stressor film for exerting a tensile stress on a channel region in a gate length direction, the first stressor film covering the first gate electrode, the first side-wall dielectric film, and the second side-wall dielectric film.