PURPOSE: To obtain a single end sealed lamp in which the wall thickness difference is reduced, and the temperature difference between the sealing part and the exhaust pipe is reduced.

CONSTITUTION: While a sealing part 3 is formed at one end of a bulb 1, an exhaust pipe 11 is connected to the other end, and an almost spherical or an elliptical luminous space is formed between the sealing part 3 and the exhaust pipe 11. In such a single end sealed lamp, the form of the luminous space is formed to make the outer form of the sealing part 3 side to the center line 0-0 between the sealing part 3 side and the exhaust pipe 11 side is made equal to or a little smaller than the outer form at the exhaust pipe 11 side to the center line 0-0. As a result, the wall thickness difference is eliminated and the mechanical strength is improved, and at the same time, the pipe side is reduced, so as to prevent generation of a thermal distortion.