A semiconductor memory device includes an electrode structure including a plurality of electrode layers and a plurality of interlayer dielectric layers which are alternately stacked on a source plate defined with a cell area and a connection area in a first direction; a vertical channel passing through the electrode structure in the cell area; a hard mask pattern disposed on the electrode structure in the connection area, and having a plurality of opening holes; a plurality of contact holes defined in the electrode structure under the opening holes, and exposing pad areas of the electrode layers; and a slit dividing the hard mask pattern into units smaller than the electrode structure in the connection area.