A semiconductor memory device may include: a stacking structure including a plurality of insulating layers and a plurality of gate electrodes alternately stacked on a substrate; a lower semiconductor pattern that protrudes from the top of the substrate; a vertical insulating pattern that extends in a vertical direction from the substrate and penetrates the stacking structure; and a vertical channel pattern on the inner surface of the vertical insulating pattern and contacting the lower semiconductor pattern, wherein an upper part of the lower semiconductor pattern includes a recess region including a curve-shaped profile, and in the recess region, the outer surface of a lower part of the vertical channel pattern contacts the lower semiconductor pattern along a curve of the recess region.