A method for supplying power performed by a power provider device including a plurality of ports according to an embodiment of the present invention may include providing power to a plurality of power consumer devices through the plurality of ports which is connected to the plurality of power consumer devices through an HDMI cable; detecting a connection release between a first power consumer device among the plurality of power consumer devices and a port; detecting a second power consumer device which is provided with insufficient power currently among the plurality of power consumer devices; notifying remaining supply power levels that are available to additionally supply to the second power consumer device; receiving a request of a power level that the second power consumer device is to receive among the remaining supply power levels; and supplying the power additionally to the second power consumer device as much as the requested power level.