When the control signal EN is changed to "H", a reference voltage VR is generated by a reference voltage generator 10, and a bias voltage BL is generated by the bias circuit 20. Based on the reference voltage VR and the bias voltage BL, a differential amplifier 30 and an output circuit 40 generates an output voltage VA. A delay circuit 50 outputs a delayed signal DL a certain delay time after the control signal EN riese. A switching signal SW used for control over the first switch 5 is made High when the control signal EN and the delayed signal DL are both High. Accordingly, it is possible to switch the voltage at the output node NO, after the output voltage VA is stabilized.