BREATHER DEVICE

PURPOSE:To surely prevent the infiltration of muddy water or the like, by providing a cylindrical main unit openably mounted into a case and a cap covering the periphery of said main unit with a clearance and specifically forming a clearance between a skirt part below the cap and the cylindrical main unit. CONSTITUTION:A breather device 1 has a cylindrical main unit 10 mounted to a hole 2a in a case 2 of a speed changer or the like, cap 20 mounted to an opening end of this main unit 10 and a valve member 30 similarly mounted inside this opening end part. The cylindrical main unit 10 has a barrel part 12 and a head part 13 formed in a contour larger than this barrel part 12, while the cap 20 has a bottom part 21 and a side cylindrical part 22 positioned holding a ventilating clearance on the periphery of said head part 13. While the side cylindrical part 22 provides in its intermediate part a partially recessed part 23, engaging it with a stepped part of the cylindrical main unit 10, thus the cap 20 is prevented from falling off. Then a clearance delta about in a size preventing a water drip from adhering is formed between a side cylindrical part below the recessed part 23, that is, a skirt part 22c and the barrel part 12.