A safety belt arrangement in motor vehicles, in which the belt has a band portion which during use runs from a real mechanism on one side of the vehicle seat, diagonally across the seat-back to a belt lock on the opposite side of the seat. The belt lock (14) is arranged so that the belt (10,11) can be disposed optionally across the front or across the back of the seat-back (3). A redirecting fitting (16;24) is joined to the seat-back and serves as a guide for the diagonal band portion when it is disposed on the back of the seat-back.