According to one embodiment, a semiconductor device includes a pillar of an oxide semiconductor material and a gate insulating layer that surrounds a side surface of the pillar. The gate insulating layer includes a lower portion, an upper portion, and an intermediate portion. A gate electrode surrounds the intermediate portion of the gate insulating layer. A lower electrode is provided that includes a first oxide conductor portion that is connected to a lower surface of the pillar. An upper electrode is provided connected to an upper surface of the pillar. The gate electrode includes a metal portion containing a metallic element and a first nitrogen-containing portion between the metal portion and the gate insulating layer. The first oxide conductor portion includes a second nitrogen-containing at an interface between the first oxide conductor portion and the gate insulating layer.