PURPOSE: To reduce errors of code reproduction at a reception level lower than a specific level by allowing a receiver which receives and demodulates a multilevel signal to vary the gain of an amplitude control signal.

CONSTITUTION: A received signal is converted to an intermediate frequency, amplitude-limited by an intermediate frequency amplifier 4 with amplitude limiting characteristics in combination, and frequency-discriminated by a frequency discriminating circuit 12. The level of a noise N in the output of the frequency discriminating circuit 12 is monitored by a correcting circuit 11 and the amplitude of a demodulation output is corrected according to the monitored level to reduce a decrease in the substantial level of a signal S at a low reception level, maintaining the multilevel discriminating function of a multilevel discriminting and regenerating circuit 6.