The present invention relates to a wireless power transmission method, a wireless power transmission apparatus, and a wireless charging system in a wireless power transmission field, and the wireless power transmission method may include receiving first information of a first wireless power receiver and second information of a second wireless power receiver that receive power in a wireless manner within a first slot among a plurality of slots, transmitting a NAK (not-acknowledge) signal to the first and the second wireless power receiver and executing a collision resolution mechanism in the first and the second wireless power receiver.