Abstract: The present invention relates to a tube coupling device comprising a coupling sleeve (1) with a persistant axial bore (2) and having a longitudinal axis (3) therein a bushing (4) for losening a coupled tube and a tube locking element (5) to be placed around a tube. In order to provide a coupling device which has a simple structure, is therefore easy to produce and which improves the bonding performance between the tube, the tube locking element and the coupling sleeve, the invention suggests that the tube locking element (5) containes first retaining means (6) pointing towards the longitudinal axis (3) and second retaining means (7) pointing away from the longitudinal axis (3), whereby the tube locking element (5) is formed integrally.