A power supply apparatus including a near-field wireless communication unit that wirelessly communicates with a plurality of communication terminals, a power transmission unit that sets a plurality of resonance frequencies to transfer power in a non-contact manner to each of the plurality of communication terminals, and a control unit that determines a priority level of each of the communication terminals based on identification information received from the communication terminals and determines an amount of power transmitted at each of the resonance frequencies based on the determined priority levels.