A linear power supply circuit is provided with: an output transistor; and a driver for driving the output transistor on the basis of the difference between a voltage based on an output voltage and a reference voltage. The driver is provided with: a differential amplifier for outputting a voltage according to the difference between the voltage based on the output voltage and the reference voltage; a capacitor one end of which has an output of the differential amplifier applied thereto and the other end of which has the voltage based on the output voltage applied thereto; a converter for converting a voltage based on the output of the differential amplifier into an electrical current and outputting the electrical current; and a current amplifier for amplifying the electrical current of the output of the converter. The supply voltage of the differential amplifier is a first constant voltage or the input voltage.