A nonvolatile memory device including: a first semiconductor layer comprising a plurality of first word lines extending in a first direction, a first upper substrate and a first memory cell array, a second semiconductor layer including a plurality of second word lines extending in the first direction, second and third upper substrates adjacent to each other in the first direction and a second memory cell array, wherein the second memory cell array includes a first vertical structure on the first upper substrate and a second vertical structure on the second upper substrate, wherein the first semiconductor layer and the second semiconductor layer share a plurality of bit lines extending in a second direction, and a third semiconductor layer under the second semiconductor layer in a third direction perpendicular to the first and second directions, wherein the third semiconductor layer includes a lower substrate that includes a plurality of row decoder circuits and a plurality of page buffer circuits, wherein the first vertical structure includes a first via area in which a first through-hole via is provided, wherein the first through-hole via passes through the first vertical structure and connects a first bit line and a first page buffer circuit, and the second vertical structure includes a first partial block, wherein the first partial block overlaps the first via area in the first direction.