PURPOSE: To prevent the deterioration in degree of separation due to the difference in the input and output characteristics of an AM and a PM detections, by mixing the outputs of matrix circuit each other and controlling the proportion of this mixture with the output of an AFC.

CONSTITUTION: Electromagnetic waves of an AM stereo system are detected at an AM detector 12 to obtain a sum signal (L+R) and at a PM detector 14 to obtain a difference signal (L-R), and the signals are applied to a matrix circuit 15. The signals spearated left and right are applied to adders 24, 23 via variable gain amplifiers 21, 22, respectively. The gain of the variable gain amplifiers 21, 22 is controlled with an AFC output picked up at an AFC low-pass filter 18. Thus, the cross talk component is canceled for left ad right signals L and R from outputs 16, 17 of adders 23, 24.