Abstract: An expansion rivet comprises a holding element (1) provided with a bearing plate (2) and legs (7). An actuating element (11) provided with a head plate (12) and a shank (13) is also present. In a locking position, the head plate (12) abuts the bearing plate (2). The engagement of expansion projections in an active region causes the legs (7) to be splayed outwardly. Attached to the shank (13) is at least one projecting detent lug (17), which is shallowly beveled away from the head plate (12) via a sliding surface (18) and is set at a steep angle confronting the head plate (12) via a reverse detention surface (19).