A semiconductor device of the present invention includes a resin package, a semiconductor chip sealed in the resin package, and having first and second pads on a front surface, a lead integrated island sealed in the resin package, to one surface of which a back surface of the semiconductor chip is bonded, and the other surface of an opposite side to the one surface of which is partially exposed from a bottom surface of the resin package as a first pad connecting terminal for electrical connection between the first pad and outside and a back connecting terminal for electrical connection between the back surface of the semiconductor chip and outside separately from each other, and a lead formed separately from the lead integrated island, sealed in the resin package, one surface of which is connected with the second pad by a wire, and the other surface of an opposite side to the one surface of which is exposed from a bottom surface of the resin package as a second pad connecting terminal for electrical connection between the second pad and outside, and the semiconductor chip is, on the one surface of the lead integrated island, disposed at a position one-sided to the first pad connecting terminal side, and the first pad and the one surface of the lead integrated island are connected by a wire.