A headset apparatus including an audio transmitter, a control circuit, a magnetic field generator and a magnetic field sensor is provided. The control circuit is configured to generate a test signal. The magnetic field generator is coupled to the control circuit to receive the test signal and generate a magnetic field accordingly. The magnetic field sensor is coupled to the control circuit and configured to sense the magnetic field and generate a sensing signal accordingly. When the control circuit detects that the magnetic field is changed based on the sensing signal, the control circuit generates a control signal to enable the audio transmitter.