A memory string comprises a semiconductor layer, a charge storage layer, and a plurality of first conductive layers. The semiconductor layer includes a columnar portion that extends in a perpendicular direction to a substrate. The charge storage layer is formed around a side surface of the columnar portion. The plurality of first conductive layers are formed around the side surface of the columnar portion and the charge storage layer. A control circuit comprises a plurality of second conductive layers, an insulating layer, and a plurality of plug layers. The plurality of second conductive layers are formed in the same layers as the plurality of first conductive layers. The insulating layer is formed penetrating the plurality of second conductive layers in the perpendicular direction. The plurality of plug layers are formed penetrating the insulating layer in the perpendicular direction. The insulating layer has a rectangular shaped cross-section with a constricted portion in a horizontal direction to the substrate. The constricted portion is positioned on a long side of the cross-section.