Abstract: The invention relates to a detachable rapid-action coupling device designed to receive a tubular plug-in element (3) having a circular retaining rib (4). Said device comprises a receiving housing (1) having a cylindrical receiving space (6) for introducing the plug-in element (3) and a separate retaining element (2) made of hard-elastic plastic material and having elastically expandable retaining edges (17) facing inwards in the shape of an arc of a circle, which edges serve to engage the retaining rib (4) from behind after the plug-in element (3) has been introduced. The retaining element (2) can be pushed in from the outside in an opening (11) of the housing wall (5) to release the plug-in element (3). The receiving space (6) consists of three stepped sections. The housing (1) is embodied as a two-part structure. In order to move the opening (11) for pushing in and releasing the retaining element (2) into a better position, if necessary, when only limited space is available.