To provide a mute circuit that prevents an output stage amplifier circuit from being destroyed at release of muting through the occurrence of a high level short-circuit or a grounding at muting.

A mute signal generated from a mute signal generating circuit at muting is given to a protection circuit that is controlled by a signal from a current detector, a voltage detection circuit of a high-level short-circuit and grounding detection circuit and a detected voltage from the voltage detection circuit and the mute signal activate the protection circuit on the occurrence of a high level short-circuit or grounding in the midst of muting and a start signal from the protection circuit deactivates the output stage amplifier circuit.