A semiconductor device (4a-4d) and a wiring device (5) are provided on a main surface of a base plate (1). A first wire (11a-11e) connects an external electrode (7a-7e) and a first relay pad (8a-8e) of the wiring device (5). A second wire (12a-12e) connects a pad (13a-13e) of the semiconductor device (4a-4d) and the second relay pad (9a-9e) of the wiring device (5). Resin (15) seals the semiconductor device (4a-4d), the wiring device (5) and the first and second wires (11a-11e,12a-12e). The second wire (12a-12e) is thinner than the first wire (11a-11e). The pad (13a-13e) is smaller than the first relay pad (8a-8e).