Abstract: A device for forming a constriction at an open end portion of a metal can having a cylindrical body includes:(1) a support member for supporting the bottom of a can and for pushing displacement thereof in an axial direction;(2) an annular anvil placed coaxially of this support member, on the side of which facing the support member an internal modeling surface is present which in the direction away from the support member has a form adapted to the desired shape of the constriction; and(3) a freely-rotating roller having a form adapted to the shape of the modeling surface, which roller can press the end portion of a positioned can forcefully against the modeling surface, which roller is carried by a support member which is driven in a circular path concentric to the annular modeling surface, wherein the axis of rotation of the freely-rotating roller extends at least approximately in the the axial direction.