A semiconductor device includes a gate electrode having a straight portion, a dummy electrode located at a point on the extension of the straight portion, a stopper insulating film, a sidewall insulating film, an interlayer insulating film, and a linear contact portion extending, when viewed from above, parallel to the straight portion. The longer side of the rectangle defined by the linear contact portion is, when viewed from above, located beyond the sidewall insulating film and within the top region of the gate electrode and the dummy electrode. A gap G between the gate electrode and the dummy electrode appearing, when viewed from above, in the linear contact portion is filled with the sidewall insulating film such that the semiconductor substrate is not exposed.