Abstract: A fastening device is disclosed for a safety belt in motor vehicles comprising a guiding member to be mounted on the vehicle frame or on some other carrier in the vehicle in such a way that a clearance is created between the guiding member and the carrier and comprising also a runner, to which one end of the safety belt or corresponding organ is attached, and which may be displaced along the guiding member to be positioned in different positions, said positions being determined by a number of holes (9) disposed along the guiding member. The guiding member is a channel-shaped rail (1) with a mid-section (2), which faces said clearance (8) and is provided with said holes (9) and with side flanges (3) projecting perpendicularly from the mid-section.