To provide an opening and closing device equipped with an outset-type guide rail which can be easily and safely mounted even by one worker and can be easily mounted even to the vicinity of a ceiling surface.

A guide rail 4 includes a base frame 15 fixed to the front surface of an upper wall with screws 13, 14, a rail body 16 guiding the travel of a runner 3, and a connection structure installed between the base frame 15 and the rail body 16. The connection structure comprises a stationary connection part 25 installed to the base frame 15, a movable connection part 26 installed to the rail body 16, and a screw body 27 non-separably fastening the rail body 16 to the base frame 15. The rail body 16 is supported by the base frame 15 in a temporary assembled state where the movable connection part 26 is connected to the stationary connection part 25. A fastening wall 33 for the screw body 27 installed to the rail body 16 is arranged below a traveling rail part 31 guiding the travel of the runner 3.