Alternatively, for example, an audio output apparatus 1C can be configured such that the facing surface 2a and the relative surface 3a are orthogonal to the central axes P and Q, and that the axial direction of the fulcrum shaft 21 is inclined with respect to the central axes P and Q (see FIGS. 25 to 27).

In the audio output apparatus 1C, 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. 26 and 27).

In the audio output apparatus 1C, 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.

In addition, for example, an audio output apparatus 1D can be configured such that the facing surface 2a and the relative surface 3a are inclined with respect to the central axes P and Q, and that the axial direction of the fulcrum shaft 21 is along the direction of the central axes P and Q (see FIGS. 28 to 30).