A ventilation member (1) comprises a support body (2), a ventilation membrane (10), and a cover part (3). The support body (2) includes a bottom surface portion (4) connected to the casing (50) and a side surface portion (5) on which the ventilation membrane (10) is installed. A first opening (4h) is formed in the bottom surface portion (4), and a second opening (5h) is formed in the side surface portion (5). The ventilation membrane (10) is installed on the side surface portion (5) so as to close the second opening (5h). The cover part (3) has a cylindrical side wall part (3b) that circumferentially surrounds the support body (2) in such a state that the support body (2) is assembled therein. The position of the second opening (5h) to be formed in the side surface portion (5) of the support body (2) is adjusted so that the ventilation membrane (10) is protected when the membrane faces the cylindrical side wall part (3b).