A sealing device for a puncture in a blood vessel, device being slidingly receivable over a guide tube and comprising a tubular, resilient sealing member formed with a sealing portion spontaneously sealable upon deployment of the device into an activated state, an engaging portion for bearing against an external surface of the blood vessel and a plurality of anchors fitted at their fore end with fasteners for engaging a corresponding internal surface of the blood vessel and at a rear end with a manipulating bit. The anchors being displaceable between a constricted position in which they blend with the tubular sealing member, and an operative position in which the fasteners are laterally expanded and engage the internal surface of the blood vessel.