NONVOLATILE SEMICONDUCTOR MEMORY DEVICE

PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device having high reliability, which can eliminate data as a bit unit from an excessively written memory cell.SOLUTION: A nonvolatile semiconductor memory device is provided, which includes a memory cell array 11 which includes non-volatile memory cells arranged at respective intersections of a plurality of bit lines and a plurality of word lines; page buffers 13 which are respectively arranged at the bit lines, and include latches storig data written/read into/from the memory cells selected by the word lines; and a control circuit 20 which decreases a threshold voltage of an excessively written memory cell on the basis of the data written in the latch if an excessive writing verify-operation detects the excessively written memory cell by determining, for each unit of the plurality of bit line, data which is read from the bit line and written into the latch of the page buffer.