An audio signal amplification device includes: a clock generation circuit that generates a clock for use in amplifying an audio signal; and a power supply circuit that generates direct current power, which is supplied to the clock generation circuit, from input power. The power supply circuit includes: a constant voltage generation circuit that generates direct current power of a constant voltage from the input power; a first capacitor; a first charging circuit that charges the first capacitor by using the input power; and a selection circuit. The selection circuit selects one direct current power of the direct current power generated in the constant voltage generation circuit and of direct current power charged to the first capacitor, and supplies the selected direct current power to the clock generation circuit.