A semiconductor memory device which includes an internal voltage generator circuit for adjusting an external power supply voltage and generating first and second internal power supply voltages. The first internal power supply voltage is supplied to a memory cell array via a first power supply line, and the second internal power supply voltage is supplied to a peripheral circuit via a second power supply line. A control circuit controls the internal voltage generator circuit so that the levels of the first and second internal power supply voltages vary depending on a mode of operation.