A switching power supply apparatus includes switching elements that generate switching current flowing through an inductor, a switching control circuit, and an inductor current detection circuit that detects current flowing through the inductor. The inductor current detection circuit is composed of a time constant circuit including a detection capacitor and a detection resistor that are connected in series to each other and is connected in parallel to the inductor. A time constant of the inductor current detection circuit has characteristics varied with frequency or temperature. This compensates variation of equivalent series resistance of the inductor with respect to the frequency or variation thereof with respect to the temperature.