A seat belt retractor has a belt reel mounted rotatably around a reel axis on a retractor frame and biased by a motive spring. A load limiter is non-rotatably connected to a rotatable spool of the belt reel. A rotor can be coupled to the belt reel and/or its load limiter by a coupling. The coupling is supported against axial displacement on an adapter flange connected rigidly to the retractor frame. The rotor transmits a torque generated by an electric motor.