First and second data retaining circuits retain data read from memory cell and threshold voltage information indicating where in one of plural threshold voltage distributions threshold voltage of memory cell is located. Calculation device executes calculations among data retained in first and second data retaining circuit and data read by sense amplifier.Control circuit executes first operation of reading data from adjoining memory cell connected to second word line adjoining first word line connected to selected memory cell and retaining the data in first data retaining circuit, and second operation of changing respective word line voltages applied to first word line for reading data or threshold voltage information among plural values and selecting one of plural data read out by the plural values based on data retained in first data retaining circuit. Third operation of externally outputting selected data is executed simultaneously with one of successive first and second operations.