PURPOSE: To make the negative feedback constant at all frequency bands and to make various characteristics such as a distortion factor and stereo separation degree constant, by mixing both output signals of a local oscillator and a voltage-controlled oscillator to obtain an intermediate signal, and mixing the intermediate signal and a high frequency signal to obtain an intermediate frequency signal.

CONSTITUTION: Output signals fL, fV of the local oscillator 7 and the voltage- controlled oscillator 8 are inputted to a mixer 9 to obtain an intermediate signal being a difference fL-fV between both signals. This intermediate signal and the high-frequency signal (f) are inputted to a mixer 10 to obtain the intermediate frequency signal having a frequency difference fi=f-(fL-fV). The signal fi is amplified by an intermediate frequency amplifier 4, a detected output is obtained by an FM detector 5 and the output is fed back negatively in FM to the oscillator 8 as a frequency control voltage. Thus, the FM negative feedback is applied to the oscillator 8 having a constant oscillating frequency to make the FM negative feedback constant independently of the tuning frequency, allowing to make various characteristics such as distortion factor and stereo separation constant over all frequencies.