PURPOSE: To position an electrode core rod accurately by inserting an assembly of an electrode core rod fitted with glass beads, a metal foil and a lead wire into the tubular sections at both sides of a bulb then press sealing while flowing inert gas.

CONSTITUTION: Tubular sections 1a, 1b are formed at both sides of a bulb 1 of a metal halide lamp while exhaust and filling branches 2 are made through the tube wall. An assembly of an electrode core rod 3 fitted with glass beads 6, metal foil 4 and lead wire 5 is inserted previously into said sections 1a, 1b and heated while flowing inert gas such as Argon through the branch 2 and glass beads 6 into said sections 1a, 1b, and after softening the metal foil 4 portion is press sealed by means of press molds 7a, 7b. Consequently the electrode core rod 3 can be supported accurately at the predetermined position by the glass beads 6 resulting in formation of a highly accurate lamp.