According to one embodiment, a semiconductor device includes first to third electrodes, first to third layers, and a first insulating layer. The first layer includes first to fifth partial regions. The first partial region is between the fourth and third partial regions. The second partial region is between the third and fifth partial regions. The first insulating layer includes first and second inter-layer regions. The second layer includes first and second intermediate regions. The first intermediate region is provided between the first partial region and the first inter-layer region. The second intermediate region is provided between the second partial region and the second inter-layer region. The third layer includes first to third nitride regions. The first inter-layer region is between the first intermediate region and the first nitride region. The second inter-layer region is between the second intermediate region and the second nitride region.