A member of the present invention is to be placed to cover a ventilation hole in order to allow passage of gas between an outside and an inside of a housing through the ventilation hole of the housing and prevent dust and/or a liquid from entering the inside from the outside through the ventilation hole. The member of the present invention includes a porous membrane having air permeability in a thickness direction and a provisional protective film joined to the porous membrane to cover the porous membrane from the outside side. The provisional protective film is air-impermeable in a thickness direction or has lower air permeability in the thickness direction than the air permeability of the porous membrane. The provisional protective film and the porous membrane are joined to each other in such a manner that the provisional protective film is removable from the porous membrane.