To improve quality in the inspection result of a medical instrument apparatus by allowing BGM to mitigate the mental stress of a patient and audio guidance to be easily heard.

When an audio signal to be inputted to a speaker 11 is not detected by an audio signal detector 12 for detecting the audio signal to be inputted to the speaker 11 for performing the audio guidance of the medical instrument apparatus 10, an audio output switching circuit 3 switches the audio signal from a player 1 for playing prescribed music into the input signal of a headphone 7, so as to allow the patient to listen to the BGM. When the audio signal to be inputted to the speaker 11 of the medical apparatus 10 is detected by the audio signal detector 12, the audio signal to be inputted to the speaker 11 is switched into the input signal of the headphone 7, so as to allow the patient to hear the audio guidance. In this case, the headphone 7 obtains the audio output of the headphone by removing noise in the circumference of the medical apparatus 10 from the music outputted from the player 1 or the audio guidance of the medical instrument apparatus 10 through the use of a noise canceler including a microphone 8, an amplifier circuit 9, and a differential amplifier circuit 5.