A phase compensation circuit, being for compensating phase of a first voltage inputted to a PWM comparator of a DC/DC converter having a sleep mode, includes: a phase compensation resistor part including a resistor; a phase compensation capacitor part including a plurality of capacitors; and a switch group arranged to change over the capacitors, in the sleep mode, to a first connection state in which at least one of the capacitors is charged with a first bias voltage and to change over the capacitors, at cancellation of the sleep mode, to a second connection state in which the first voltage is set to a desired initial value.