A semiconductor device includes: a first conductivity type semiconductor of a nanostructure; a first electrode that is in ohmic junction with an end part of the first conductivity type semiconductor; a second electrode that is coupled to the first electrode and is provided over a side surface of the first conductivity type semiconductor; and a depletion constituent that controls expansion of a depletion layer inside the nanostructure, wherein the depletion layer is expanded inside the first conductivity type semiconductor by the depletion constituent in a direction intersecting a movement direction of a carrier.