A switching element with a small current capacity is provided to be able to be used in a DC-DC converter. The DC-DC converter includes a switching circuit in which a first switching element, a second switching element, a third switching element, and a fourth switching element are connected in series, a flying capacitor that is connected between a connection portion between the first switching element and the second switching element and a connection portion between the third switching element and the fourth switching element, a reactor that is connected between a connection portion between the second switching element and the third switching element and a positive electrode of an input unit, and a control circuit that turns on/off the switching element, in which the control circuit turns on/off the switching elements so that a peak value in a reactor current becomes equal to or smaller than a predetermined value.