A neck ring holder device intended to be used at a mould for forming glass containers (30), wherein the neck ring (41) for realizing the mouth (32) of the container can be opened and consists of a plurality of circumferential sectors (44) that can be moved apart from a closed position of the neck ring (41), in which the circumferential sectors (44) are coplanar and form a substantially continuous annular element, up to an open position of the neck ring (41), in which the circumferential sectors (44) are rotated out of said coplanar configuration, moving away from each other, about axes directed perpendicular to the direction of the axis (45) of said annular element, is characterised in that the movement of the circumferential sectors (44) from the closed position to the open position.