A manufacturing method of a semiconductor device comprises: providing a first insulating film whose relative dielectric constant is at most a predetermined value above a substrate; providing a second insulating film whose relative dielectric constant is greater than the predetermined value on a surface of the first insulating film; forming a recess for a wire through the second insulating film and extending into the first insulating film, and also forming a recess for a dummy wire through the second insulating film and extending into the first insulating film spaced from a formed area of the recess for the wire; providing a conductive material inside the recess for the wire and the recess for the dummy wire; and providing a wire inside the recess for the wire and providing a dummy wire inside the recess for the dummy wire by polishing and removing the conductive material.