Abstract: A semiconductor integrated circuit has a function of providing an internal voltage having little dependency on a variation of external power supply voltage comprises a reference voltage generating circuit which outputs a first output corresponding to a reference voltage, a voltage converting circuit which outputs a second output, a level of which is in accordance with an outer power source voltage, a voltage-decrease/boosting selecting circuit which receives first and second outputs and outputs a third output resulting from comparing a level of the first output with a level of the second output, a level of the third output being changed when a level of the outer power source voltage exceeds a prescribed value.