PURPOSE: To increase the area for gas-liq. contact and to remove harmful components and dust effectively by providing a conical body and an iron ring having a circumferential edge part of a triangular section in the outlet end of a Venturi scrubber thereby providing double-ringlike gaseous passages.

CONSTITUTION: A nozzle member 5 consisting of a circular conical body 5a, a circular conical ring 5b and a fixing metal 7 is provided in the outlet of the Venturi scrubber 4 of a treating device for combustion gases. Since gaseous passages 6a, 6b are doubled by such device, the area for gas-liq. contact is increased, the harmful components and dust in the combustion gases are removed more effectively and the size of the treating device is reduced.