A wireless power transmission unit according to the present invention transmits power wirelessly from a power transmitting section 100 to a power receiving section 200 through a resonant magnetic field. The unit includes: the power transmitting section 100, which resonates at a resonant frequency f0; at least one relay section 300, which can resonate at a frequency that is selected from multiple frequencies including the resonant frequency f0; and a resonance control section 600 that outputs information that specifies a resonance condition to be imposed on the relay section 300 according to the arrangement of the power receiving section 200 and that makes the relay section 300 resonate on the resonance condition that has been specified in accordance with that information.