PURPOSE: To obtain an FM demodulating state display with which a tuning operation is facilitated and the demodulating state can be easily understood, by analyzing and displaying the working state of an FM signal demodulator over a number of items.

CONSTITUTION: The output of an FM wave detector is fed to a light emission control circuit 32 via an integrator 31. For this circuit 32, the light emission control voltage that has its peak when the FM wave detection level obtained with a center frequency fc is supplied is delivered, and the light emission control voltage is gradually changed to the same direction in response to the light emission control voltage having a shift in the positive and negative direction on the basis of the frequency fc. Then the light emission control voltage is applied to a light emitting element 34. On the other hand, a switch circuit 35 is provided to a current path of a light emitting means 34. The circuit 35 is controlled when the output level of an intermediate frequency amplifier 15 is higher than a prescribed value. Thus the means 34 can be turned on.