A first resistance element is coupled between a first rectifying element and an output node at which a reference voltage is generated. Second and third resistance elements are coupled in series between a second rectifying element and the output node. A differential amplifier outputs a control voltage corresponding to a difference between a first voltage generated at a connection point of the first rectifying element and the first resistance element and a second voltage generated at a connection point of the second resistance element and the third resistance element. A control circuit supplies a control current corresponding to the control voltage from the differential amplifier. A start-up circuit causes, by supplying a start-up current to the output node in response to supply of a power supply voltage, transition from a first stable state to a second stable state.