the invention relates to a device for stopping a container having a neck , said device comprising a stopper and a cap consisting of a plastic material and able to surround both the stopper and the neck . the cap comprises a ring that can surround the stopper and the neck when mounted and is provided with means for locking onto the neck , and a body for handling the ring , provided with first means for transmitting a thrust force to the ring and second means for activating means for locking the ring . the ring is provided with a continuous outer peripheral collar , and the handling body is provided with at least one raised element designed to abut against the continuous outer peripheral collar when it activates the locking means .