PURPOSE: To enable a user to always secure an antenna matching and a best receiving without controlling the antenna length by switching and connecting an antenna matching circuit element to a main antenna in response to the division ratio of a variable divider of a PLL synthesizer receiver.

CONSTITUTION: The FM receiving frequency of 76.0-90.0MHz are equally divided into four bands, and the matching loading coils 11-13 are switched in each band. Then the center frequency of each band is set as f1=77.75MHz, f2=81.25MHz, f3=84.75MHz, and f4=88.25MHz respectively. Thus the band is divided every 3.5MHz, and the coils 11-13 and an antenna 10 are set so that an antenna matching is secured at each frequency of f1-f4. Then the coils 11-13 are switched in accordance with the division ratio (N value) of a variable divider 7 set at five different levels of receiving frequency.