Abstract: A fastening device for a safety belt in motor vehicles comprises 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 (40) or recesses disposed along the guiding member. The guiding member is a channel-shaped rail (30) with a web-section (39), which faces the clearance (39) and with side flanges (32) which first project from the web-section and then turn inwards towards each other. The in-turned parts (34) form between them a longitudinal channel (35) and are provided with said recesses or holes.