Seat belt retractor

The belt retractor for a passenger restraint system has a frame, a belt spool (18) rotatably mounted in the frame, and a locking mechanism (24, 30) for selective blocking of the belt spool. A locking gear (24) provided with external teeth is attached to a flange (22) of the belt spool. A pawl (30) is preloaded by a spring (36) into engagement with the locking gear (24). An electromagnet (34) keeps the pawl (30) out of engagement with the locking gear (24) during normal operating mode of the belt retractor.