A mounting unit (1) serves to rotatably and captively fasten a screw (2) to a mounting part (3), especially the fastening eyelet (4) of a belt buckle of an automobile, a truck or a different commercial vehicle. The mounting unit (1) includes a screw (2) including a head (5), a shank portion (6) and a threaded portion (7) including a thread (8), the shank portion (6) being arranged in a region between the head (2) and the threaded portion (7). The mounting unit (1) furthermore includes a mounting ring (10), the mounting ring (10) being arranged on the shank portion (6) not to be movable in a direction of the screw axis (11), the mounting ring (10) including at least one retaining element (13) being designed and arranged such that a mounting part (3) can be pushed over and beyond the retaining element (13) in a way that the mounting part (3) can be fastened by the retaining element (13) such that the screw (2) is arranged to be rotatable with respect to the mounting part (3) and not to be movable in the direction of the screw axis (11).