Seat belt buckle, in particular for racing vehicles

A seat belt buckle (1), in particular for racing vehicles, having: a casing (2) defining at least one slot (5) engageable by an end member (6) of a strap of a seat belt for connection; a lock mechanism (7) housed in the casing (2) and for releasably retaining the end member (6); and a release lever (8) fitted to the casing (2) and movable, from a rest position, along a path lying in an actuating plane to release the lock mechanism (7) from the end member (6), the release lever (8) having an end (12) projecting from the casing (2) in the actuating plane as the release lever moves along the path. The buckle (1) also has a lever guard portion (21) fitted to the casing (2) and having a lateral surface, an ideal extension of which in a direction perpendicular to the actuating plane surrounds the end (12) of the release lever (8) in the rest position.