Ventilation member and vented housing using the same

A vented housing with a ventilation member which is fixed to an opening portion of said housing, comprising: a breathable film transmitting gas passing through the opening portion of the housing in a state in which said breathable film is fixed to said opening portion ; and a support including a supporting portion for supporting said breathable film and an insertion portion to be inserted into said opening portion of said housing; wherein a lock structure for locking said support in said housing by rotating said support around a central axis of said support is formed in said insertion portion, and wherein said support includes a seal portion on a surface of said supporting portion facing said housing, said lock structure comprises a plurality of protrusions in an outer circumference of an insertion-start-side end portion of said insertion portion, and arranged at an equal interval in a circumferential direction of said insertion portion and a plurality of fitting grooves for fitting the protrusions thereto are formed in the inner surface of said housing.