A switching power supply device includes an output voltage detection unit that outputs an output voltage detection value. The control circuit includes: a target voltage generation unit that generates an output voltage setting value; an A/D conversion unit that A/D converts an error between the output voltage setting value and the output voltage detection value; a digital compensation unit that computes an amount of control based on an output signal of the A/D conversion unit; and a PWM signal generation unit that generates a PWM signal for the switching element based on the amount of control. The target voltage generation unit detects a standby state based on the output voltage detection value, the output signals of the A/D conversion unit and the digital compensation unit, and in the standby state, switches the output voltage setting value to a second value lower than a value for another state.