A wireless power charging system has a wireless power transmission apparatus formed to charge a plurality of wireless power receiving apparatuses located in a short distance therefrom, wherein the total charging time for the wireless power receiving apparatuses is saved. The wireless power transmission apparatus has a main control unit and a resonant converter unit, which transmit the electric signal to the wireless power receiving apparatus via the resonance signal generated from a primary charge core in order to change the wireless power receiving apparatuses. The wireless power transmission apparatus also includes an output signal conversion module for transmitting a converted electric signal to the resonant converter unit and a received signal process module for processing a signal transmitted form the wireless power receiving apparatus.