A semiconductor chip is mounted on a first surface of a substrate, the substrate having wiring formed on the first surface, so that a circuit formation surface of the semiconductor chip faces the first surface of the substrate and that electrodes provided on the circuit formation surface are connected with the wiring. A sealing resin layer is then formed on the first surface of the substrate to cover the semiconductor chip. The sealing resin layer and the semiconductor chip are ground starting from a surface opposite to the circuit formation surface to thin the semiconductor chip.