A non-volatile memory device is provided. The non-volatile memory device includes: sub-blocks provided on a substrate. The sub-blocks include: a first sub-block connected to a first word line group including a first number of word lines; and a second sub-block connected to a second word line group including a second number of word lines. The first sub-block includes: at least one first memory cell storing M-bit data; and second memory cells each storing N-bit data. The second sub-block includes: at least one third memory cell storing K-bit data; and fourth memory cells each storing L-bit data. M, N, K, and L are positive integers, N is greater than M, and L is greater than K. The first number and the second number are different, and the at least one first memory cell and the at least one third memory cell include different numbers of memory cells.