To provide a mounting structure of a light-shielding unit which plays a role of rotation stop of the light-shielding unit of respective bushings of a switch, and which can be mounted easily.

An electric wire connecting terminal 1 is compressed and fixed to the tip of the center conductor 6 in which the main body insulator 5 mounted on a case or the like of the switch or the like is penetrated and fixed. Moreover, the light-shielding unit retaining tool 2 has an inner face fitted to a compressed and fixed part 1e of the electric wire connecting terminal 1, and furthermore, the outer periphery of the light-shielding unit retaining tool 2 has the same shape fitted to the inner face of the light-shielding unit 3. In addition, the light-shielding unit retaining tool 2 is made multi-split, and a gap is installed so as to be closely fitted when fitted to the electric wire connecting terminal 1. Moreover, the light-shielding unit 3 is formed of an elastic resin or rubber. For that reason, the light-shielding unit 3 and the light-shielding unit retaining tool 2 are closely fitted to the electric wire connecting terminal 1. Furthermore, two walls are installed at the inner face of the light-shielding unit, and it is regulated from moving in the axial direction because of those walls. Accordingly, mounting can be carried out surely and easily by a small number of members.