Thus, the audio output apparatus 1 is fitted in the ear 100 in a state where the base body 2 is in contact with the opening edge of the ear canal 113 and the rotating body 3 is at least partially inserted into the cavity of concha 114. Therefore, it is made possible to ensure that the audio output apparatus 1 is stably fitted in the ear 100 with the audio output apparatus 1 protruding from the ear 100 by a limited amount.

Moreover, the rotating body 3 rotated relative to the base body 2 is at least partially brought into contact with the antihelix 105 or the inferior crus of antihelix 107.

Thus, the audio output apparatus 1 is fitted in the ear 100 in a state where the base body 2 is in contact with the opening edge of the ear canal 113 and at least part of the rotating body 3 is in contact with the antihelix 105 or the inferior crus of antihelix 107. Therefore, the position at which the base body 2 is in contact with the ear 100 is separated from the position at which the rotating body 3 is in contact with the ear 100, and it is made possible to ensure that the audio output apparatus 1 is stably fitted in the ear 100.

Furthermore, the facing surface 2a and the relative surface 3a are inclined with respect to the planes orthogonal to the central axes P and Q, respectively, and the axial direction of the fulcrum shaft 21 is along the direction orthogonal to the facing surface 2a.