A memory device includes first to nth decks respectively coupled to first to nth row lines which are stacked over a substrate in a vertical direction perpendicular to a surface of the substrate, n being a positive integer, a first connection structure extending from the substrate in the vertical direction to be coupled to the first row line, even-numbered connection structures extending from the substrate in the vertical direction and respectively coupled to ends of even-numbered row lines among the second to nth row lines, and odd-numbered connection structures extending from the substrate in the vertical direction and respectively coupled to ends of odd-numbered row lines among the second to nth row lines. The even-numbered connection structures are spaced apart from the odd-numbered connection structures with the first row line and the first connection structure that are interposed between the even-numbered connection structures and the odd-numbered connection structures.