A non-volatile memory device includes a substrate, a memory cell string including a vertical channel structure and memory cells, a voltage generator including a first transistor and configured to provide various voltages to the memory cells, and a vertical capacitor structure. The vertical capacitor structure includes first and second active patterns apart from each other in a first horizontal direction, a first gate pattern located above a channel region between the first and second active patterns, a first gate insulating film between the first gate pattern and the substrate in a vertical direction, and capacitor electrodes each extending in the vertical direction. The first transistor includes a second gate pattern and a second gate insulating film between the second gate pattern and the substrate in the vertical direction. The first gate insulating film has a thickness greater than a thickness of the second gate insulating film in the vertical direction.