A semiconductor device that allows easy hole extraction is provided. The semiconductor device includes: a semiconductor substrate having drift and base regions; a transistor portion formed in the semiconductor substrate; and a diode portion formed adjacent to the transistor portion and in the semiconductor substrate. In the transistor portion and the diode portion: a plurality of trench portions each arrayed along a predetermined array direction; and a plurality of mesa portions formed between respective trench portions are formed, among the plurality of mesa portions, at least one boundary mesa portion at a boundary between the transistor portion and the diode portion includes a contact region at an upper surface of the semiconductor substrate and having a concentration higher than that of the base region, and an area of the contact region at the boundary mesa portion is greater than an area of the contact region at another mesa portion.