PURPOSE: To elevate the performance of a receiver in case of a strong input, by applying an AGC signal to the input terminal of the high frequency amplifier circuit through the switching transistor.

CONSTITUTION: An intermediate frequency signal which has been output from the transistor 7 is detected by the diodes 15, 16 through the capacitor 14, and becomes the voltage according to the signal input. The AGC is executed by applying this voltage to the base of the switching transistor 21, and connecting the emitter to the gate of the high frequency amplification FET3. In case of a strong input, the transistor 21 is turned on, the negative potential of the terminal 23 is applied to the gate of FET3, the gain is lowered, and therefore the gain can be adjusted effectively.