PURPOSE: To improve the sensitivity of a long wave band and that of a medium wave band by using the defogger of an automobile rear part window as a part of an antenna for long/medium wave band and selecting an antiresonance point by a choke coil and a resonance point by a matching circuit.

CONSTITUTION: The branch line 6a of an antenna 6 is capacity-coupled by approaching the branch line 3a of the defogger 3, which makes the defogger 3 function as a part of the antenna. A reactance circuit 8 permits a DC to flow, however, blocks a high frequency current received by the defogger. A first antiresonance point is located in a long wave broadcast frequency band by coils 30, 31 and capacitors 32, 33, and a second antiresonance point in a medium wave broadcast frequency band, and the resonance point in the midway between the long wave broadcast frequency band and the medium wave broadcast frequency band, respectively. Also, the reception current of an FN broadcast frequency band is blocked by coils 12a, 12b. Moreover, the resonance point is located in the medium wave band by impedance on matching circuit 7 and defogger 3 sides and input impedance on a receiver.