A microphone device includes an audio signal output circuit that balanced-outputs, through a balanced transmission line, an audio signal output from a condenser microphone unit, a balanced output terminal including a hot terminal, a cold terminal, and a ground terminal connected to the balanced transmission line, a power supply circuit that supplies a phantom power supply to the audio output circuit from the balanced output terminal through the balanced transmission line, and a display circuit including light emitting elements that perform lighting and non-lighting according to an operation of a manual switch, and the display circuit includes constant current elements that generate a constant current through the balanced transmission line, a constant voltage element connected to the constant current elements and which generates a constant voltage, and light emitting elements connected to the constant current elements, and to which the constant voltage by the constant voltage element is applied.