A power supply apparatus is disclosed. The power supply apparatus to supply power to an electronic apparatus includes a first relay and a second relay which are turned on and off to control power supply with respect to the electronic apparatus, and a processor configured to control a switching operation of the first relay and the second relay based on at least one of a connection detection signal indicating connection of the power supply apparatus and the electronic apparatus, and a power on/off signal indicating a power on/off command with respect to the electronic apparatus.