A tightening device for a safety belt includes a cable having a first end and a second end. A drive is connected to the first end of the cable. The drive, when activated, moves the cable in a tightening direction. The second end of the cable is connected to a safety belt. A deflection device about which the cable is guided is provided. The deflection device has a rotatable eccentric pawl and a stop. The stop limits rotation of the eccentric pawl when rotated upon movement of the cable in the tightening direction and thus defines a deflection position of the eccentric pawl. The eccentric pawl has an elongate extension extending in a direction of the cable portion extending between the drive and a deflection location at the deflection device. The eccentric pawl has a deflection end guiding the cable at the deflection location. The eccentric pawl has an eccentric arc opposite the deflection end. A counter plate is positioned opposite the eccentric pawl and the cable is guided between the counter plate and the eccentric pawl. The eccentric arc is a return lock preventing movement of the cable in a return direction opposite the tightening direction by engaging the cable and locking the cable in the return direction.