A surface area of a transverse cross section of an upper portion of a columnar portion is greater than a surface area of a transverse cross section of a lower portion of the columnar portion. A configuration of the transverse cross section of the upper portion is a triangle or a pseudo-triangle having three corners, or a quadrilateral or a pseudo-quadrilateral having four corners. A configuration of the transverse cross section of the lower portion is substantially a circle. The upper portion of the columnar portion is adjacent to an upper layer portion of a stacked body including a control gate of an uppermost layer of control gates. The lower portion of the columnar portion is adjacent to a lower layer portion of the stacked body including a control gate of a lowermost layer of the control gates.