Abstract: In a belt buckle for safety belts, particularly in motor vehicles, for receiving and locking an insertable tongue having a housing and, arranged therein, an insertion path for the insertable tongue, with the path containing a spring-loaded ejector, and having a locking element which is pivotably mounted in the buckle and, in the locked position, engages in the tongue recess and is secured in the locked position via a securing member movably mounted in the buckle, and having a slidable actuator for releasing the locking element, which is guided in the housing transversely with respect to the plane of movement of the locking element and which, to protect it from shock, cooperates with a counterweight guided in the housing, the intention is to simplify the construction of the buckle for the purpose of shock prevention and reduce the mass of the parts which cooperate in the event of acceleration of the buckle.