The present invention relates to wireless power transmission. A method for controlling a communication connection for a wireless charging device supporting in-band communication and out-band communication, according to an embodiment of the present invention, may comprise: a step of receiving a first packet from a device through in-band communication; a step of generating a power transmission contract on the basis of the first packet; a step of performing an out-band communication connection on the basis of the power transmission contract; a step of controlling power by using out-band communication when the out-band communication connection is successful.