A semiconductor memory device includes a plurality of semiconductor patterns extending in a first horizontal direction and separated from each other in a second horizontal direction and a vertical direction, each semiconductor pattern including a first source/drain area, a channel area, and a second source/drain area arranged in the first horizontal direction; a plurality of gate insulating layers covering upper surfaces or side surfaces of the channel areas; a plurality of word lines on the upper surfaces or the side surfaces of the channel areas; and a plurality of resistive switch units respectively connected to first sidewalls of the semiconductor patterns, extending in the first horizontal direction, and separated from each other in the second horizontal direction and the vertical direction, each resistive switch unit including a first electrode, a second electrode, and a resistive switch material layer between the first and second electrodes and including carbon nanotubes.