A memory device includes an active region with a drain; a plurality of memory blocks arranged in a first direction; and a plurality of pass transistors formed in the active region and sharing the drain, each one of the plurality of pass transistors configured to transfer an operating voltage from the drain to a corresponding one of the plurality of memory blocks in response to a block select signal. The plurality of pass transistors is divided into first pass transistors and second pass transistors. A channel length direction of the first pass transistors and a channel length direction of the second pass transistors are different from each other.