A reference current generating circuit generates at least one reference current. A voltage generating circuit generates voltage. A sense amplifier compares a current caused to flow in a memory cell according to the voltage supplied from the voltage generating circuit with the reference current supplied from the reference current generating circuit. A control section is supplied with an output signal of the sense amplifier. When verifying the threshold voltage of the memory cell, the control section causes the voltage generating circuit to generate verify voltage which is the same as readout voltage generated at the time of data readout from the memory cell.