PURPOSE: To reject the interference waves with a simple constitution, by performing control through the change of respective voltage of the control voltage signals in positive and negative polarity.

CONSTITUTION: The synthesizer 17 is connected between the two outdoor antennas 3, 4 and the end of antenna side of the feed line 6 for reception signal leading in, to synthesize the signal inputted from the antennas 3, 4 and to output it to the feeding line 6. Further, the control section 7 is provided at the end at room side of the feed line 6. Further, the control voltage signals of positive and negative polarity incoming via the feed line 6 from the control section 7 are mutually separated and added to the variable phase shifter 15 and the variable attenuator 16, which is performed with the control signal separation circuit 18. On other hand, the control section 7 outputs the control voltage signal of positive or negative polarity to the feed line 6 and the voltage value is made variable at the phase shift amount adjuster 23 to output the control voltage signals of positive or negative polarity to the feed line 6, and the voltage value is made variable at the attenuation adjuster 24. Thus, the interference waves can be rejected with a simple constitution.