A nonvolatile semiconductor memory device includes a memory array and an X-decode section. The memory array includes a plurality of nonvolatile memory cells arranged in a matrix form and a plurality of word lines. The X-decode section selects a selected word line selected from the plurality of word lines, supplies a negative voltage to the selected word line, and supplies a positive voltage to unselected word lines which are not the selected word line, at the time of an erase operation.