SEMICONDUCTOR MEMORY DEVICE

A semiconductor memory device according to one embodiment of the present invention is provided with a laminated body (SK), a columnar body, a conductive member (SL), a plate-shaped part (ST2), and a breaking part (IP). In the laminated body (SK), a plurality of conductive layers (WL) and a plurality of insulating layers (OL) are alternately laminated layer by layer, and a step portion (SR) is formed by the conductive layers (WL) at an end portion in the first direction. The columnar body penetrates through the stacked body (SK), and a memory cell is formed at a portion facing the conductive layer (WL). The conductive member (SL) is electrically connected to the columnar body below the laminated body (SK), and extends beyond the step section (SR) in the first direction to a region (PA) on the side of the laminated body (SK). The plate-shaped section (ST2) extends in the region (PA) in the lamination direction of the laminated body (SK), reaches the conductive member (SL), and extends in a second direction inte