A semiconductor device includes a substrate over which a circuit is formed, a multi-layer wiring layer having a plurality of wiring layers formed over the substrate and a pad formed in a predetermined location of an uppermost layer of the wiring layers, a new pad provided in an appropriate location over the multi-layer wiring layer, and a redistribution layer provided with a redistribution line coupling the new pad and the pad. In the semiconductor device: the multi-layer wiring layer includes a signal line for transmitting an electric signal to the circuit and a ground line provided in a wiring layer between the redistribution line or the new pad and the circuit; the ground line is formed to correspond to a location where the new pad is assumed to be located and a route along which the redistribution line is assumed to be formed; and the redistribution line is formed along at least a portion of the ground line.