The present specification which relates to a wireless power transmission device and a control method, capable of transmitting and receiving power wirelessly comprises a power supply unit for supplying power to a receiving device to transmit power wirelessly; and a power transmission control unit for, periodically generating a waveform with a particular frequency, measuring an attenuation coefficient of the waveform at each cycle, measuring a variation in the attenuation coefficient at each cycle, and determining the type of an external material. The present invention has a technical feature wherein the power transmission control unit determines whether to transmit power wirelessly to the receiving device on the basis of the type of the external material.