Disclosed is a nonvolatile memory device which includes a plurality of cell array layers stacked on a semiconductor substrate. Each of the plurality of cell array layers includes a plurality of strings. Each of the plurality of strings has string and ground select transistors and a plurality of memory cells connected in series between the string and ground select transistors. A common source line is on each of the plurality of cell array layers. Each common source line is connected with first sides of the plurality of strings on a corresponding cell array layer. A plurality of bit lines is connected with second sides of the plurality of strings disposed on the cell array layers and arranged in the vertical direction to the semiconductor substrate. A plurality of word lines is connected with the plurality of memory cells.