Provided is a semiconductor device. The semiconductor device includes an insulating layer extending in a first direction. A first vertical channel pillar is disposed separately from the insulating layer. A first interconnection line extends in a second direction perpendicular to the first direction, and is electrically connected to the first vertical channel pillar. A first bit line extends in the second direction, and crosses over the first interconnection line and the first vertical channel pillar. A first bit contact overlaps the first interconnection line, and electrically connects the first interconnection line to the first bit line. A length of the first bit contact in the second direction is greater than a length of the first bit contact in the first direction.