Abstract: A locking device for a rapid uncoupling connection assembly including a fixed part consisting of a receptacle), a releasable part able to become separated from the receptacle consisting of a plug equipped with a locking and unlocking device of the connection assembly in which latter the connector corresponding to the releasable part includes two interior and exterior concentric rings, the interior ring carrying erasable means of coupling actuated so as to be able to occupy two functional positions, namely a blocking position and an unblocking position, the exterior ring including means of blocking and unblocking of the two functional positions, in which the interior ring is a claw socket consisting of a ferrule provided with sectors defining the cantilever beams, the socket being arranged between the receptacle of the fixed part and the exterior ring of the releasable part.