Patent ID: 8467562

Claim:
An ear canal fitting unit comprising: a tube configured to be capable of being inserted into an ear canal; an electrode configured to have flexibility and be so disposed along an outer circumferential surface of the tube that a predetermined gap is formed between the electrode and an inner surface of the ear canal; pressing means for deforming the electrode in such a direction as to get away from the outer circumferential surface of the tube and pressing the electrode against the inner surface of the ear canal; and suppressing means for suppressing push-back of the electrode pressed against the inner surface of the ear canal, wherein one end of the electrode is fixed to one end part of the tube, the pressing means is formed of a member that slides on the outer circumferential surface of the tube in a longitudinal direction of the tube, and the other end of the electrode is fixed to the member, the suppressing means switches a degree of suppression of push-back in a stepwise manner and is formed of a mechanism for releasably fixing a position of the member, the member has a tube shape and has such a shape as to be fitted in a cavum conchae, the ear canal fitting unit is provided at a leading end of a hook-shape member capable of being hooked on a root of an auricle, and the hook-shape member is provided with an amplifier that amplifies potential difference between the electrode and a reference electrode provided at a tail end of the hook-shape member attachably to an earlobe.