VENTILATION STRUCTURE

A housing (10) is provided with an opening (11) having a tapered surface (12). A vent member (2) to be attached to the opening (11) includes a support body (3) having a vent passage (30), a waterproof gas-permeable membrane (4), and a cover (5). The support body (3) has a base portion (31) to which the waterproof gas-permeable membrane (4) is bonded, and a stem portion (32) extending from the base portion (31) so as to be engaged with an inside surface of the housing (10). The stem portion (32) is fitted with a seal member (6), and this seal member (6) is pressed against the tapered surface (12) in the opening (11) by a pressing portion (34).