Abstract: The disclosure relates to an expanding plug intended for closing a cylindrical aperture provided in a wall and accessible from only one side. In one embodiment, the plug comprises a base which is applied against the front face of the wall, at least two gripping members which are inserted into the aperture with their ends protruding on the other side of the aperture, which are provided with an outwardly extending radial shoulder, and which are mounted for sliding in corresponding recesses provided in a central member, permitting their radial displacement through a pivoting displacement effected in the plane of the radial recesses, a screw control into the central member in order to effect simultaneously their radial displacement towards the outside and their longitudinal displacement in the direction of the rear face of the wall until the shoulders of the gripping members are applied against the rear face of the wall.