The invention relates to a belt buckle (2) for a lap belt (1), comprising a housing (3) having a first end (31) and a second end (32). A slide (4) is arranged between the first end (31) and the second end (32) in a movable manner. At least one spring element (341, 342) is designed to push the slide (4) in the direction of the second end (32). At least one rod (411, 412) is arranged on the slide (4) in such a way that it extends in the direction of the second end (32). Two clamping jaws (5, 6) are rotatably arranged on the second end (32) of the housing (3). Said clamping jaws comprise torsion spring elements (51, 52) that push them into a closed position. When the at least one spring element (341, 342) is in an idle position, the at least one rod (411, 412) pushes the clamping jaws (5, 6) into an open position (81). When the at least one spring element (341, 342) is in a compressed position, the at least one rod (411, 412) does not push the clamping jaws (5, 6) into the open position (81). They are then pushed into the closed position (32) by the torsion spring elements (51, 52). The lap belt (1) is attached, on one end thereof, to a belt attaching element (351, 352) on the second end (32) of the housing (3). With the other end, the lap belt is guided through a belt-guiding region between the slide (4) and the clamping jaws (5, 6).
