Provided is a power supply apparatus for supplying power to an external electric device. The power supply apparatus includes: a power outlet unit, to which a power plug of the external electric device is coupled, to supply electricity to the external electric device; a power control unit controlling power supply from the power outlet unit to the external electric device; and a user interface unit connected to the power control unit to receive a power activation code from a user, wherein the power control unit supplies power from the power outlet unit to the external electric device during a usage period corresponding to the power activation code.