A wire short-circuit defect during molding is prevented. A semiconductor device has a tab, a plurality of leads arranged around the tab, a semiconductor chip mounted over the tab, a plurality of wires electrically connecting the electrode pads of the semiconductor chip with the leads, and a molded body in which the semiconductor chip is resin molded. By further stepwise shortening the chip-side tip end portions of the leads as the first edge or side of the principal surface of the semiconductor chip goes away from the middle portion toward the both end portions thereof, and shortening the tip end portions of those of first leads corresponding to the middle portion of the first edge or side of the principal surface which are adjacent to second leads located closer to the both end portions of the first edge or side, the distances between second wires connected to the second leads and the tip end portions of the first leads adjacent to the second leads can be increased. As a result, it is possible to prevent the wire short-circuit defect even when wire sweep occurs due to the flow resistance of a mold resin.