A memory device includes memory cells, the memory cells each including a first gate, a second gate electrically isolated from the first gate, a first gate insulating layer including a data storage layer having a ferroelectric material and disposed between the first gate and a channel region, a second gate insulating layer disposed between the second gate and the channel region, a first switching cell connected between the memory cells and a source line, and a second switching cell connected between the memory cells and a bit line. The second switching cell includes a third gate, a fourth gate, a third gate insulating layer not including a data storage layer having the ferroelectric material and the third gate disposed between the third gate and the channel region, and a fourth gate insulating layer disposed between the fourth gate and the channel region.