A semiconductor chip is sealed by resin without covering an outer terminal of a semiconductor device having a power transistor. A semiconductor chip having a power transistor is housed within a recess of a metal cap while a drain electrode on a first surface of the semiconductor chip is bonded to a bottom of the recess via a connection material. A gate electrode and a source electrode are formed on a second surface opposite to the first surface of the semiconductor chip, and the gate electrode and the source electrode are bonded with metal plate terminals 6G, 6S via connection materials 5b, 5c. In addition, the semiconductor chip is sealed by a resin sealing body with mounting-surfaces of the metal plate terminals 6G, 6S being exposed. Mounting surfaces of the metal plate terminals 6G, 6S and a third part of the metal cap are bonded to electrodes on a mounting board 10 via connection materials 5e, 5f and 5g.