High-pressure mercury vapor discharge lamp (1) comprising a lamp vessel (2) made of a transparent ceramic material, enclosing a discharge space (3) comprising an ionizable discharge medium and at least two electrodes (4,5), each provided with an electrode tip (4a, 5a), which tips are spaced apart at a mutual distance d, and electrical feed-through elements (6,7) which extend from the electrodes (4,5) to the exterior, wherein the distance d between the electrode tips (4a,5a) is less than 1.0 mm and the mercury density in the vessel (2) is higher than 0.3 mg/mm 3 .