An improved method is described for the manufacture of mercury dispenser devices to be used in fluorescent lamps, of the type wherein the dispenser material (2) is contained inside a metal tube (1), these dispensers providing a more uniform distribution of mercury, with lower fluctuations from one device to the other. This is obtained by a method according to which a tubular metal container (1') having a larger diameter than the final one (1), after the filling thereof with said dispenser material (2) is passed between at least two pairs of rollers (3, 3', 4, 4') whose axes of rotation are parallel to each other and perpendicular to the advancing direction (X-X') of the tubular container (1), until a reduction of the cross-section of the latter to the desired value is obtained, and is finally cut to the right size into the single dispenser elements .