Abstract: In a device for mounting in position guide rails (1), in which device the guide rail (1) is free of perforations and is seized by claws (3), which claws (3) are fixed in a mounting part, the mounting part has a mounting plate (2) extending in parallel relation to the longitudinal direction of the guide rail, noting that the claws (3) can be passed through perforations (16) in the mounting plate and can be braced against the mounting plate (2), in particular with the interposition of a spring (4), at the side, located opposite the guide rail (1), of the mounting plate (2).