A memory device includes a stack structure, in which a common source line is formed, and a peripheral circuit structure overlapping the stack structure when viewed in plan view and comprising a common source line driver configured to discharge the common source line. The common source line driver includes a first common source line driving unit, electrically connected to the common source line through a first network and configured to discharge the common source line, and a second common source line driving unit electrically connected to the common source line through a second network, different from the first network, and configured to discharge the common source line. The first common source line driving unit and the second common source line driving unit are controlled independently of each other.