To obtain the high selection characteristic by forming a double-tuned circuit by the primary and secondary tuning circuits and connecting a parallel resonance circuit between the primary tuning circuit and an input terminal, to reduce the inductance value of a 3rd coil.

A double-tuned circuit is formed when a coil L1 of a primary tuning circuit is magnetically connected to a coil L2 of a secondary tuning circuit. The coils L1 and L2 and a coil L3 of a parallel resonance circuit are formed by the air core coils, where the lead wires are wound round respectively. Both coils L1 and L2 are placed close to each other, to secure magnetic connection between them with the number of turns of the coil L2 set larger than that of the coil L1. The coils L1 to L3 are connected to a band filter 15 which is formed for each of capacitors C4, C5 and C6 by each of the patterns which are formed on the rear side of a small substrate. Thus, the band filters are mounted on the small substrate and are therefore controlled beforehand in a state where the variance of transistor characteristics is included. In this way, the high selection characteristic is obtained.