A semiconductor device includes bit lines extending along a first direction, the bit lines being arranged along a second direction intersecting the first direction, a plurality of channel layers disposed under the bit lines, the plurality of channel layers extending in a third direction perpendicular to a plane extending along the first and second directions and spaced apart along the second direction, so that each channel layer is at least partially overlapped with at least two of the bit lines, and a contact plug extending, from the channel layer, toward one of the bit lines overlapped with the channel layer.