Disclosed are a wireless power transmitter and a method of transmitting power thereof. The wireless power transmitter to wirelessly transmit power to a wireless power receiver includes a transmission coil to receive power from a power supply apparatus, and a transmission resonance unit to transmit the power received therein from the transmission coil to the wireless power receiver using resonance. The transmission resonance unit includes an inner loop, and an outer loop connected to the inner loop while surrounding the inner loop.