A semiconductor device includes a semiconductor pillar and a control electrode. The semiconductor pillar extends in a first direction, and includes a first region, a second region and an intermediate region provided along the first direction. The intermediate region is positioned between the first region and the second region. The control electrode is disposed at a position so that the control electrode faces the intermediate region via an insulating film. The semiconductor pillar is provided so that a minimum width of the intermediate region in a second direction perpendicular to the first direction is narrower than a first width of the first region in the second direction and a second width of the second region in the second direction.