A sliding cover includes an outside plate, a structural member fixed to the rear face of the outside plate, a movable holding member disposed between the outside plate and the structural member, and a toggle disposed between the holding member and the outside plate or the structural member. The holding member includes two parallel racks and guiding portions disposed at both end portions and extending in the same direction as the racks. The holding member includes a holding plate; an even number of pinions meshed with each other and supported by the holding plate so as to be rotatable; and guiding components supported by the holding plate. The pinions, disposed between the guiding components, are meshed with the racks, and the guiding components are engaged with the guiding portions so as to be slidable. The biasing direction in which the toggle biases the holding member is reversed substantially at the midpoint of the movable range of the holding member.