Abstract: A low-pressure mercury vapor discharge lamp according to the invention is provided with a discharge vessel (10) which encloses a discharge space (11) containing mercury and a rare gas in a gaslight manner. The discharge vessel (10) has a light-transmitting tubular portion (12) and a first and a second end portion (13A, 13B). Current supply conductors (20A, 20A'; 20B, 20B') issue through each end portion (13A, 13B) to respective electrodes (21A, 21B) arranged in the discharge space (11). The lamp is further provided with a main amalgam (30) for stabilizing the mercury vapour pressure in the discharge space (11) during normal operation, and with an auxiliary amalgam (31A, 31B) for quickly releasing mercury into the discharge space (11) after switching-on of the lamp. In an equilibrium state at room temperature (25.degree. C.), the mass (m.sub.Hg in mg) of the quantity of mercury absorbed in auxiliary amalgam (31A, 31B) is at most 20 times the mercury vapour pressure (P.sub.