PURPOSE: To atomize fuel such as gasoline fine and uniformly in an atomizing device used for an automobile or the like.

CONSTITUTION: A hollow body 2 with such external shape as to be small in diameter at the upper part, gradually swollen toward the lower part, then slightly contracted and, with the interior formed into a cylindrical hollow space is disposed in an venturi. A sliding body 5 is accommodated in the hollow space of the hollow body 2, and the sliding body 5 can be vertically moved by an operating rod 11. The outer peripheral upper part of the sliding body 5 is formed into a close contact part 6 brought into close contact with the inner peripheral surface of the hollow body 2. The lower edge of the close contact part 6 is formed of an inclined edge 8 and a vertical edge 7, and the lower part of the inclined edge 8 is formed into a clearance part 10 with a clearance to the hollow body 2. Small holes 3 are opened in a row at the whole periphery of the hollow body 2. Fuel entering the clearance part 10 through a pipe 4 flows out of the hollow body 2 from the small holes 3 so as to be atomized. The outflow of fuel is regulated by moving the sliding body 5 vertically and increasing/decreasing the number of the small holes 3 opened to the clearance part 10.