Performance of a semiconductor device is enhanced. A semiconductor device is a semiconductor device obtained by sealing in a sealing portion first, second, and third semiconductor chips each incorporating a power transistor for high-side switch, fourth, fifth, and sixth semiconductor chips each incorporating a power transistor for low-side switch, and a semiconductor chip incorporating a control circuit controlling these chips. The source pads of the fourth, fifth, and sixth semiconductor chips are electrically coupled to a plurality of leads LD9 and a plurality of leads LD10 via a metal plate. As viewed in a plane, the leads LD9 intersect with a side MRd4 of the sealing portion and the leads LD10 intersect with a side MRd2 of the sealing portion.