PURPOSE: To attain a sound muting circuit capable of operation at either time of power on or power off.

CONSTITUTION: The sound muting circuit consists of a 1st transistor(TR) 1 constituted of a PNP type TR capable of supplying power supply (5V) to its emitter through a diode, connecting a resistor 5 and a capacitor 6 connected in series between the emitter and the earth and outputting a mute signal or the like supplied to its base from its collector as an inverted mute signal or the like, a 2nd TR 2 constituted of an NPN type TR capable of executing switching operation for intermittently connecting a sound output to the earth, a 3rd TR 3 constituted of a PNP type TR for outputting a reset signal supplied to its base from its collector as an inverted reset signal, an amplifier 4 for amplifying a supplied sound signal and generating a sound output, the resistor 5, the capacitor 6, and the diode 7 connected from the power supply to the emitter of the 1st TR 1 in the forward direction.