A fastening element for attaching plate-shaped boards, and including a large-surface clamping member (2;22) with a hollow-stem (3;23) projecting from opening in the clamping member (2,22) with a hollow stem (3;23) projecting from and having a bore (5;25) opening in the clamping member (2;22) for receiving an expansion member (14) for an anchoring member (4;14); and a plug-shaped member (9;29) attached to the clamping member (2;22) with a strap (8;28) for closing the bore and having a plug-in section (11) with a sealing surface (12;32) sealing by cooperating with the bore wall and is force-lockingly retained therein, with the plug-in section (11;31) having at least one recess (13;33) provided with an undercut and a largest diameter of which corresponds to a diameter of a stem (15) of the expansion member (14) for enabling the closing member (9;29) to eclipse the shaft (15) of the expansion member (14).