The method of manufacture includes preparing a wiring board which has a front surface and an opposing rear surface, a plurality of conductive portions which are formed on the front and rear surfaces of the core material thereof, respectively, forming a first resist film and a second resist film on the front surface and rear surface of the core material, respectively, such that the conductive portions are exposed therefrom; mounting the semiconductor chip to the main surface side of the wiring board via adhesive material; electrically connecting the pads provided on the semiconductor chip, with the first conductive portions of the wiring board via bonding wires, respectively; and sealing the semiconductor chip and the bonding wires.