A semiconductor device according to an embodiment includes: a semiconductor substrate; a fin formed on the semiconductor substrate; a gate electrode formed so as to sandwich both side faces of the fin between its opposite portions via a gate insulating film; an extension layer formed on a region of a side face of the fin, the region being on the both sides of the gate electrode, the extension layer having a plane faced to a surface of the semiconductor substrate at an acute angle; and a silicide layer formed on a surface of the plane faced to the surface of the semiconductor substrate at an acute angle.