The transmitter of a wireless power transmission audio system includes: a transmission signal generating section for generating a transmission signal comprised of an RF signal; a first resonant circuit which receives and sends out the transmission signal; a detecting section for sensing a variation in the transmission signal; and a transmission signal adjusting section. The loudspeaker of the system includes: a second resonant circuit for receiving the transmission signal by producing a magnetic field resonant coupling phenomenon; and an audio output section for reproducing the audio signal. At least one of the transmitter and the loudspeaker includes an impedance adjusting section which changes an impedance value on the transmission line of the transmission signal. When the impedance adjusting section changes the impedance value, the transmission signal adjusting section changes the signal waveform of the transmission signal.