PURPOSE: To uniformly distribute liquid water at a high density in a spray pattern and to remarkably enhance a spray effect by bringing compressed air into collision with the fluid jet in a central part from an outer side downstream of an orifice.

CONSTITUTION: The compressed air is delivered through a circular opening 45 into an annular cavity part 60. This annular cavity part 60 is zoned to a diffusion delivery end 55 of the orifice 35 and the adjacent inside surface of an end cap 40. The inside of the end cap 40 having the annular cavity part 60 rotates by mixing the air stream from the circular aperture 45. The air stream flows to an inner side toward the central part of the central aperture 42 in the end cap 40. Since the annular slot 62 is included in the end cap 40, the compressed air collides against the fluid from the orifice 35 via the annular slot 62 and the fluid is sprayed in the pattern of a cone shape.