An appliance for sealing elastic hoses with a sleeve, which is plastically deformable and slipped onto the hose, has two jaws which are movable towards and away from each other. One jaw has two straight bars which project towards the other jaw and extend transversely of the sleeve to make two transverse indentations in the sleeve and the hose when the jaws are moving towards each other. The same jaw has a cutting edge which projects towards the other jaw and is directed transversely of the sleeve, the cutting edge making a substantially transverse cutting indication in the sleeve and the hose when the jaws are moving towards each other.