Abstract: A wind-up device for a vehicle safety belt, which device includes a housing, a winding system composed of a winding drum mounted in the housing for automatically winding up the belt so that a portion of the belt is wound around the drum, the drum being locked in the direction of unwinding when a given operating state occurs, and a belt braking device which includes a rotatably mounted brake roller partially surrounded by the belt and mounted for displacement between a normal position in which it is free to rotate and, when the winding drum is blocked, a braking position in which it opposes movement of the belt, movement into the braking position being effected by the tension forces acting on the belt, the braking device further including a bias spring mounted to urge the brake roller into its normal position and in which the brake roller is mounted to be displaced under the force of the belt tension to brakingly contact the outer turn of the belt portion wound on the drum.