There is provided an internal voltage generating circuit that reliably supplies a constant internal voltage to the interior of a semiconductor device without regard to an external voltage, where the internal voltage generating circuit compares a first reference voltage with a first internal voltage fed back to generate the first internal voltage following the first reference voltage, receives the first internal voltage to generate a second reference voltage which is more insensitive to fluctuation of the external voltage than the first reference voltage, and compares the second reference voltage with a second internal voltage fed back to generate the second internal voltage which follows the second reference voltage and has a variation gradient smaller than that of the first internal voltage when the external voltage is changed, thereby supplying the second internal voltage to a circuit requiring stabilized internal voltage, which is obtained to increase stability and durability of the operation of the semiconductor device.