To achieve energy-saving by reducing whole amount of ventilation while keeping the amount of flue gas while using existing facilities having a hood.

The attachment has a covering disc body which is formed into a disc shape for covering a large diameter end in the hood, in which an opening having an area of ≤1/5 of the area of the large diameter end opening is formed, and which has a fitting wall fitting to the outside of the hood in the outside fringe thereof, and a suction pipe of the same diameter as the opening attached to the disc body while communicating to the opening, smoke is sucked from the lower end of the suction pipe.