Downsizing of an inductor is achieved while reducing radiation noise of an inductor current. A boosting power supply unit is, for example, provided in an ECU mounted in a vehicle or the like. The boosting power supply unit has a boosting coil, a switching element and a current control unit 16. The current control unit 16 controls the switching element 12 to turn on and off by using a clock signal CK1 with a higher frequency than a pulse signal SPL in a clamping period when the inductor current flowing in the boosting coil is clamped at a preset peak setting current, and controls the switching element to turn on and off by using the pulse signal SPL in periods other than the clamping period. By controlling the switching element to turn on and off in this manner, the inductor current flowing in the boosting coil is controlled.