A nonvolatile semiconductor memory includes a first power supply voltage pad to which a first power supply voltage required for a writing, reading or erasing operation of the memory cells is applied. The nonvolatile semiconductor memory includes a second power supply voltage pad to which a second power supply voltage that is lower than the first power supply voltage and to be supplied to the I/O circuit is applied. The nonvolatile semiconductor memory includes a first voltage down-converting circuit that converts the first power supply voltage down to a first down-converted voltage that is higher than the second power supply voltage. The nonvolatile semiconductor memory includes a second voltage down-converting circuit that converts the second power supply voltage down to a second down-converted voltage that is lower than the first down-converted voltage.