The invention relates to a fastening device (2) for a wall-hung sanitary object (1). The fastening device (2) has a holder (11) for mounting the fastening device (2) on a wall (15). On the holder (11), a support element (12) is movably arranged, in which an engagement element (13) is mounted, which is inserted into an opening (7) of the sanitary object (1) and is movable relative to the holder (11). In order to enable a quick and easy disassembly of the sanitary object (1), the support element (12) according to the invention transverse to an insertion direction (E) of the fastening device (2)in the opening (7) of the sanitary object (1) is movable relative to the holder (11).