An FMX stereophonic receiver receives an FMX stereophonic broadcast signal which includes a stereo sum signal, an uncompressed stereo difference signal, and a compressed stereo difference signal which is formed by modulating the uncompressed stereo difference signal by a quadrature modulation and being compressed. The FMX stereophonic receiver includes an FM detector for producing an FM detection signal including a stereo pilot signal, a PLL circuit for producing a signal which is in a synchronized relationship with the stereo pilot signal included in the FM detection signal, a synchronous detection circuit for receiving the FM detection signal and for producing the uncompressed stereo difference signal in accordance with the signal produced from the PLL circuit, a quadrature detection circuit for receiving the FM detection signal and for producing the compressed stereo difference signal in accordance with the signal produced from the PLL circuit, and a phase shifting means for shifting the phase of at least one of the FM detection signal applied to the PLL circuit and the FM detection signal applied to the detection circuits so as to correct the phase difference between the synchronous detection signal and the signal to be detected.