Disclosed is a wireless power transmission system. The wireless power transmission system includes a power transmitter including a first resonant circuit and wirelessly transmitting power using a resonance, at least one repeater including a second resonant circuit resonating with the first resonant circuit, and a power receiver disposed between the power transmitter and the repeater, including a third resonant circuit magnetically resonating with the first and second resonant circuits, and receiving power from the power transmitter and the repeater. If the power transmitter and the repeater are installed in an indoor space, such as a room or an office room, and the power receiver is installed in a mobile device, such as a cellular phone, the mobile device is automatically charged in the indoor space. The power transmission efficiency is improved by installing the power receiver between the power transmitter and the repeater. The received power is adjusted according to the alignment direction of the power receiver.