PURPOSE: To simplify the circuit constitution by using a de-emphasis circuit for FM stereo signal and a low pass filter as the circuit for sound multiplex signal.

CONSTITUTION: An FM multiplex circuit 5 in an FM stereo demodulating circuit 1 functions as a buffer amplifier to the sound multiplex signal to output the sound multiplex signal to two left and right circuits. This signal passes through a left de-emphasis circuit 6 and the low pass filter 7, a high frequency component is compensated and a main sound signal is applied to a matrix circuit 3. Further, a signal inputted to a sub-signal demodulating circuit 2' is extracted for a sub-sound signal at a band pass filter 8, FM-detected and applied to analog switches 16, 17. Then, only the sub-sound signal detected is applied to the matrix circuit 3 via a right de-emphasis circuit 6, operated with the main sound signal and the sound signal of both left and right channels is outputted.