Abstract: The object of the present invention is to provide a reference voltage generation circuit which is arranged to obtain the stability of a reference voltage Vref both at the time of start of the power source voltage and at the time of fluctuation of the power source voltage for the reference voltage generation circuit that generates a high reference voltage (Vref). When closing the power source, a low level signal and a high level signal are output from a power source start circuit. These signals are received by a started circuit to thereby make all transistors therein "on" and thereby output a stable reference voltage Vref. The starting characteristic is improved compared to that of a conventional reference voltage generation circuit, whereby the starting has become possible to attain. Even when the power source voltage sharply fluctuates, a stable reference voltage Vref can be output.