Provided is a semiconductor device which is small in size and in which the deformation of leads is prevented at the time of wire-bonding. The semiconductor device includes: an island; a semiconductor element mounted on the bottom surface of the island; leads provided close to the island; and a sealing resin for integrally sealing these constituents. Moreover, in the semiconductor device according to the present invention, electrodes on the semiconductor element are bonded to the leads provided adjacent to a side of the island, the side not provided with leads which extends continuously from the island.