To increase the efficiency of an operation for fixing an end part cap to a hollow molded body.

This non-contact type protective device (particularly, an optical grid) comprises a light emitting unit and/or a light receiving unit stored in a case formed as the hollow molded body 2. At least one end face of the hollow molded body 2 is closed by an end part cap 4. When the end cap 4 is fitted to the hollow molded body 2 and fixing pins 17 are inserted into positioning holes 16 and 42 from one side face (side on which a cover plate 5 forming a light emitting face and/or a light receiving face) of the hollow molded body 2, the end part cap 4 is fixed to the hollow molded body 2. Thus, as compared with a method for fixing the end part cap 4 with a plurality of screws, not only the operation can be easily performed but also the protective device can be manufactured at lower cost because a screw hole must not be formed in the hollow molded body 2.