PURPOSE: To obtain correct light distribution by forming recessed dimples near both ends of a tube-shaped sealed body and coupling and fixing ring sections of supporters on both ends of a filament assembly while a tensile force is applied to the filament assembly.

CONSTITUTION: Recessed dimples 11 are formed in advance near both ends of a tube-shaped sealed body 1, the phase of a recess 28 where the dimple 11 of a ring section 27 can pass is made to pass together with the dimple 11, a filament assembly 2 is slightly rotated, the ring section 27a is coupled with the dimple 11, for example. A tensile force is applied to the filament assembly 2 to slightly extend it, the ring section 27a is coupled with the other dimple 11. The filament assembly 2 is arranged along the tube axis of the tube-shaped sealed body 1 while a tensile force is applied between the ring sections 27a and 27b, the length of the boundary section of luminous sections 21a and 12b located on both ends with internal leads is maintained after the pressing and sealing processes of the portion corresponding to the molybdenum foil 25 of the tube-shaped sealed body 1, end correct light distribution is obtained.