In a semiconductor device, a plurality of semiconductor chips included in an upper-arm circuit are connected in parallel between a pair of upper-arm plates, while a plurality of semiconductor chips included in a lower-arm circuit are connected in parallel between a pair of lower-arm plates. In each of the arm circuits, the plurality of semiconductor chips are arranged in a direction perpendicular to a direction in which emitter electrodes and pads are arranged, the pads are disposed on the same side of the emitter electrodes, and signal terminals extend in the same direction. A series-connecting part between the upper- and lower-arm circuits includes a joint part 20 continued to respective side surfaces of the corresponding upper- and lower-arm plates. Each of inductances of respective parallel-connecting parts of the upper- and lower-arm plates which connect the semiconductor chips in parallel is smaller than an inductance of the series-connecting part.