Abstract: Belt lock for a safety belt with a plug-in guide provided in a lock-housing for a belt plug-in tongue. The tongue can be arrested in the plug-in guide by a latch mechanism, and can be unlocked by operation of a pressure element against the force of a spring. The plug-in tongue is provided at one side at a longitudinal edge with an engagement detent in which a latch of the locking mechanism can engage. The tongue has a guide profile at its forward end, seen in the plug-in direction which profile fits only at the correct insertion mode with a mating surface in the plug-in guide.