PURPOSE: To obtain a discharge lamp having a lamp holder with high dielectric strength by forming a front and rare through hole in a region between a pair of lead support holding parts of a lamp holder by molding.
CONSTITUTION: A united body of a terminal 23 and a lead support 22 and a united body of a terminal 25 and a lead support 24 are united with an insulating base 20 by insertion molding. A front and rare through hole 42 is formed in the base region between the lead supports 22, 24 by molding. Consequently, since the wall where the front and rare through hole are formed is molded by dies by pressing closely, the material density of the periphery of the hole 42 becomes high and whisker formation at the time of molding a lamp holder 20 is suppressed. The increase of the dielectric strength following the increase of the material density overcomes the decrease of the dielectric strength following the formation of an air layer equivalent to the through hole 42 and thus the dielectric strength of the lamp holder 20 in a region between a pair of terminals is heightened. As a result, a discharge lamp apparatus having excellent insulating property in the region between both terminal supporting parts is obtained.