The package size of a semiconductor device is brought close to chip size, and a miniaturization is aimed at. Including a semiconductor chip having a plurality of pads, a plurality of leads having a mounting surface and a wire connection surface, having a thick portion, and the thin portion whose thickness is thinner than a thick portion, and with which the length of each wire connection surface was furthermore formed shorter than a mounting surface, a plurality of wires connecting leads with a semiconductor chip, and a molded body formed with resin, by arranging so that the thin portion of each lead dives into the lower part of a semiconductor chip and connecting the lead and the semiconductor chip with the wire by reverse bonding, securing the length of the mounting surface of each lead, distance from the side face of a semiconductor chip to the side face of a molded body is shortened as much as possible, package size is brought close to chip size, and the miniaturization of QFN 5 is aimed at.