Abstract: A memory device capable of enlarging an interval between a source selection transistor and a memory cell adjacent to the source selection transistor, enlarging an interval between a drain selection transistor and a memory cell adjacent to the drain selection transistor, or enlarging the intervals between the source selection transistor and the memory cell adjacent to the source selection transistor and between the drain selection transistor and the memory cell adjacent to the drain selection transistor, prevents the memory cell adjacent to the source or drain selection transistor from being degraded in programming speed due to program disturbance.