A semiconductor device including a second insulating film formed on a substantially flat surface, on which a surface of a first wiring and a surface of a first insulating film are continued, to cover the first wiring, a wiring trench formed in the second insulating film, connection holes formed in the second insulating film to extend from the wiring trench to the first wiring, dummy connection holes formed in the second insulating film to extend from the wiring trench to a non-forming region of the first wiring, and a second wiring buried in the connection holes and the wiring trench to be connected electrically to the first wiring and also buried in the dummy connection holes, and formed such that a surface of the second wiring and a surface of the second insulating film constitute a substantially flat surface.