PURPOSE: To perform stable ejection operation by providing holes for fining of jets near a nozzle port, ejecting the jets flatly through said holes and ejecting compressed air thereto.

CONSTITUTION: The leading end of a nozzle body 1 is formed to a circular conical shape, and a nozzle port 3 is provided in the top part thereof. An annular projecting line part 6 is provided around the leading end part of the body 1 of an air ring 2. The outside circumferential surface 7 of the part 6 is formed to a spherical shape, and a pair of holes 8 for fining of jets are punched on the inside circumferential surface side. A pair of projecting parts 11 are provided on the respective diametral sides of the holes of the ring 2, and holes 12 for flattening of jets are disposed in the parts 11. The holes 12 are communicated respectively with an introduction hole 9 for compressed air.