A power supply apparatus for supplying power in a wireless manner or a wired-wireless manner is provided. The power supply apparatus includes a power conversion unit converting input power into first power, and a wireless power supply unit varying a switching frequency switching the first power to wirelessly transmit the switched first power in one of a first wireless transmission manner or a second wireless transmission manner or wirelessly transmit the switched first power at a frequency within a resonance frequency band of one wireless transmission manner of wireless transmission manners having different resonance frequency bands.