According to one embodiment, a semiconductor device includes first and second gate electrodes, a semiconductor layer, an output electrode, and an insulating layer. The semiconductor layer includes first source and drain areas, a first channel area facing the first gate electrode, second source and drain areas, and a second channel area facing the second gate electrode. The output electrode outputs voltage produced in the first and second drain areas. In the semiconductor device, the first drain area is in contact with the second drain area. The insulating layer includes a hole portion communicating with one of the first and second drain areas. The output electrode is in contact with one of the first and second drain areas via the hole portion.