Nonvolatile memory device

PURPOSE: A non-volatile memory device is provided to increase storage capacity and to increase the reliability of a memory device. CONSTITUTION: A memory cell array is classified into a plurality of blocks. Each block includes a plurality of memory cells. A plurality of the memory cells is arranged in an area which crosses a plurality of word lines and a plurality of bit lines. At least one word line is classified into an upper word line group and a lower word line group.