The lamp according to the invention has a metal holder part 2 with a rece in which the pinch seal 10 of the lamp bulb 1 is clampingly fixed with the aid of a plurality of support tabs 21a, 21b, 22a, 22b, 23a, 23b. In order to reduce the danger of damage to the pinch seal 10 when the lamp is being mounted on its base, the pinch seal 10 is tapered is graduated fashion toward the base, and all the support tabs 21a, 21b, 22a, 22b, 23a, 23b that act upon the pinch seal 10 are oriented toward the broad sides of the pinch seal 10, which is substantially rectangular in cross section, while the narrow sides of the pinch seal 10 are located in the holder part 2 without touching it. The narrow sides of the pinch seal (10) are retained in the holder (2) spaced from the holder. Guide ribs (50a, 50b) are formed on the pinch seal (10) positioned off-center, and laterally relatively staggered. Support tabs (21, 20b) fitting against the pinch seal in the region of the guide ribs, are formed with recesses (24a, 24b), which are wider than the width of the guide ribs, and also laterally staggered and offset so that the rib-and-recess combination provide for reliable lateral positioning of the lamp in the base, by laterally positioning the pinch seal in the base, and, further, ensuring that the seal cannot cant upon insertion of the lamp in the base. The ribs and recesses can be so arranged to form, respectively, right and left lateral abutment and support surfaces.