PURPOSE: To prevent the deterioration of a living environment by collecting dust together with open air into a suction/collection machine through reinforced opening on a cover part, a suction port, and a duct by means of a suction machine for improving the work efficiency and eliminating a pneumoconiosis of an industrial disease from a workshop.

CONSTITUTION: A cover part 5 is reinforced and given an opening 6. The opened part is connected to a suction port 8, which receives the suction of a suction machine 13 via a duct 19. Dust is discharged to a dust collector 14 by the suction machine via the duct. Frames 7 bent along the direction of wind at the opening part reduce the resistance of the wind, while the opening part reinforced by bending and welding prevents the damage of a peripheral plate 10 of the cover caused by shocks. In the case of a work by a grinder, the dust inevitably generated can be perfectly sucked and collected.