Abstract: The present invention relates to a belt buckle (10) for a length-adjustable aircraft safety belt, wherein the belt buckle (10) comprises: a main body (12) which defines a receiving space (20); a holder (14) for attaching a belt strap (16) of an aircraft safety belt; and a locking device (18) for latching a buckle tongue on the main body (12) for closing the aircraft safety belt, wherein the main body (12) comprises a base plate (40) and side cheeks (42) projecting therefrom at two opposite sides, wherein the base plate (40) forms a substantially plane base surface (44), and wherein the holder (14) is mounted on the side cheeks (42) in a movable manner and a clamping edge (38) of the base plate (40) facing the holder (14) projects from the base surface (44) in the direction of the holder (14), so that the holder (14) is drawn to the clamping edge (38) when a tensile load is applied to the belt strap (16) and the belt strap (16) is clamped between the clamping edge (38) and the holder (14), so that a lengt