There is provided a lock device for an opening/closing body that is attached to an opening portion of a fixed body so as to be openable and closable. The lock device includes lock portions, a pair of rods, a manipulation unit, and a link unit. The opening/closing body or the fixed body has an installation surface on which the link unit is installed, and the installation surface is provided with a holding portion which holds the link unit. One of the base portion and the holding portion is formed with a bendable elastic engagement piece or pieces, and the base portion is installed on the installation surface as a result of the elastic engagement piece or pieces being engaged with the other of the base portion and the holding portion.