According to one embodiment, a semiconductor device includes first to fourth semiconductor regions, a first electrode, and a first insulating film. The first semiconductor region includes a first partial region and a second partial region. The second semiconductor region is separated from the first partial region. The third semiconductor region is provided between the first partial region and the second semiconductor region. The third semiconductor region includes a third partial region and a fourth partial region. The first electrode is separated from the second partial region and is separated from the second semiconductor region and the third semiconductor region. The first insulating film includes a first insulating region and a second insulating region. The fourth semiconductor region includes a first portion. The first portion is provided between the fourth partial region and at least a portion of the first insulating film.