Semiconductor device and method of manufacturing semiconductor device

According to one embodiment, in a semiconductor device, a stacked body is disposed above a substrate. In the stacked body, a conductive film and an insulating layer are alternately disposed in a stacking direction. A semiconductor columnar member penetrates the stacked body in a stacking direction. An insulating film surrounds the semiconductor columnar member. The insulating film penetrates the stacked body in the stacking direction. A pattern is disposed at a position adjacent to or close to a region. The region includes a penetration plug. The penetration plug extends from a position same as or above an upper end of the stacked body to a position below a lower end of the stacked body in the stacking direction. The pattern has a quadrangular or disjoined quadrangular shape.