A waterproof cover can prevent substantial deformation thereof and maintain high waterproof performance even when temperature inside the waterproof cover changes. The waterproof cover has a peripheral wall composed of a rubber or elastomer. Two end portions of the peripheral wall are connected to an attachment member. The peripheral wall has an attachment hole passing through the peripheral wall in a thickness direction. A ventilation film is provided inside the attachment hole as an inner pressure adjustment member to adjust inner pressure of the waterproof cover.