PURPOSE: To increase the distortion eliminating capability, by adding an FM detection output signal to a function device having a characteristic reverse to that of an IF filter amplitude, and adding the output of the function generator and the AM detection wave output.

CONSTITUTION: The detection output of an FM detector 5 is inputted to a function device 21 haing a characteristic reverse to the amplitude characteristic of an IF filter 3, the function device 21 makes a signal having a characteristic reverse to the AM detection output signal component produced at the filter 3, and is inputted to an adder 22. The output of an AM detector 7 is inputted to the adder 22, the output of the adder 22 is signal canceling the amplitude modulation produced at the filter 3, and the amplitude modulation component only produced at the multipath is obtained. The output of the adder 22 is inputted to a function generator 8 producing the coefficient of the multipath distortion component and the output is processed at a multiplier 12, adders 9, 11 and a delay device 10, allowing to eliminate the multipath distortion.