A battery cover including a main body, an opening/closing part provided on the main body, a flexible rib having a locking projection provided on the opening/closing part, an abutting rib provided on the main body, which has a locking recess to be engaged with the locking projection while the opening/closing part is opened to the main body, a contact portion that abuts on the locking projection and deflects the flexible rib when the opening/closing part is opened to the main body, and a flat portion provided on the contact portion, which abuts on the locking projection first when the opening/closing part is opened to the main body and extends in the direction orthogonal to the direction of force input when abutting on the locking projection.