Disclosed are a wireless power transmitter and a wireless power transmission method thereof. The wireless power transmitter, which wirelessly transmits power to a wireless power receiver, includes a power source to generate AC power, a transmission coil receiving power from the power source to generate a magnetic field, a transmission resonance coil coupled with the transmission coil to transmit power generated by the magnetic field to the wireless power receiver using resonance, and a detector detecting an existence state of the wireless power receiver by detecting power transmitted through the transmission resonance coil.