In a power supply circuit, a first switching transistor and a second switching transistor are serially connected between another-side terminal GND and a one-side terminal VCC of an input power supply, and a third switching transistor and a fourth switching transistor are serially connected between the one-side terminal VCC of the input power supply and a boosted output terminal OUT. A shift capacitor is provided between a connection point of the first and second switching transistors and a connection point of the third and fourth switching transistors, and a holding capacitor is connected to the boosted output terminal OUT. A back gate switching circuit for switching a voltage to be applied to the back gate is provided for the third switching transistor.