A power supply circuit for a DRAM has a power-on detection circuit which detects when an external power supply potential reaches a predetermined potential and produces first and second detection signals, and an internal power supply circuit which generates an internal power supply potential. The power supply circuit further has a first intermediate potential generating circuit which generates a first intermediate potential from the external power supply potential and supplies it to an intermediate potential supplying node and, when the first detection signal is produced and the first intermediate potential reaches a predetermined potential, stops the supply of the first intermediate potential to the intermediate potential supplying node and the intermediate potential generating function, and a second intermediate potential generating circuit which generates a second intermediate potential from the internal power supply potential and, when the second detection signal is produced, supplies the second intermediate potential to the supplying node. The first intermediate potential generating circuit has a larger driving capability than that of the second intermediate potential generating circuit. It is made possible to shorten the rising time of the intermediate potential after the power is switched-on and to reduce the overall current consumption.