A data storage device includes a nonvolatile memory device including a target memory cell and one or more adjustment memory cells sharing bit lines with the target memory cell, one or more of the adjustment memory cell are adjacent memory cells adjacent to the target memory cells, and suitable for reading out data therefrom or storing data therein; and a controller suitable for adjusting threshold voltages of the adjustment memory cells based on threshold voltages it of the target memory cell and the adjacent memory cells.