A power feeding device which wirelessly supplies power to a power receiver receives a position and resonant frequency detection signal from the power receiver, detects the position and the resonant frequency of the power receiver, and controls the frequency of a power signal to be transmitted to the power receiver on the basis of the information. As the power signal for power transmission, two signals having different frequencies, which are generated using a mixer by mixing a base carrier (a first signal) with a conversion carrier (a second signal) generated on the basis of the resonant frequency, are used.