To provide a mechanism capable of freely setting the operating stroke of parallel synchronized opening and closing operations, and further of movement without using any other mechanism.

One side of a chain is locked to a moving plate 7. Sprockets 4, 5 with brake mechanisms are installed in a moving plate 6, and a chain 1 is laid over the sprockets. The sprockets 2, 3 are driven by a motor 10. When a brake is operated to rotate the motor 10 clockwise, the moving plates 6, 7 are synchronized with the rotation to operate to be opened. When the motor 10 is rotated counterclockwise, the moving plates are synchronized with the rotation to operate to be closed. A brake 8 is operated to release a brake 9. When the motor 10 is rotated clockwise, the moving plates 6, 7 are moved to the sprocket 3 side while the distance before their operation is maintained. When the motor 10 is rotated counterclockwise, the moving plates 6, 7 are moved to the sprocket 2 side while the distance before their operation is maintained.