In the audio output apparatus 1D, the length of the fulcrum shaft 21 along the axial direction is variable. Rotation of the rotating body 3 relative to the base body 2 is started in a state where the fulcrum shaft 21 in the non-rotation state is elongated and the rotating body 3 is spaced away from the base body 2 in the axial direction of the fulcrum shaft 21 (see FIGS. 29 and 30).

In the audio output apparatus 1D, since the length of the fulcrum shaft 21 along the axial direction is made variable, the distance between the base body 2 and the rotating body 3 can be changed by changing the length of the fulcrum shaft 21. Therefore, the rotating body 3 can be rotated smoothly relative to the base body 2.

Furthermore, the rotating body 3 can be rotated relative to the base body 2 without regard to the inclination angles of the facing surface 2a and the relative surface 3a with respect to the central axes P and Q, thereby improving the flexibility in design.

Note that according to examples of the audio output apparatuses 1C and 1D described above, the length of the fulcrum shaft 21 along the axial direction is variable, and the rotating body 3 is spaced away from the base body 2 in the axial direction of the fulcrum shaft 21; however, another configuration may be possible in which the length of the fulcrum shaft 21 along the axial direction is fixed, and the rotating body 3 is moved from the fulcrum shaft 21 in the axial direction of the fulcrum shaft 21 so that the rotating body 3 is spaced away from the base body 2 in the axial direction of the fulcrum shaft 21.