To embed a current limiting element without requiring trouble in injecting a filler and improve the heat radiation property of the current limiting element by filling the filler by the help of vacuum.

A partitioning member 41 is so placed that a bottom wall 41a of the partitioning member 41 should cover an insertion hole 38 and a slot 39 formed in a bottom 33a of a receiving body 33 and a side wall 41b of the partitioning member 41 should cover a border 37a between a lower space 36 and a side space 37 along the side surface of the receiving body 33. The lower space 36 and the side space 37 in the hollow part of the receiving body 33 are partitioned by the partitioning member 41, the lower space 36 becomes a current limiting element receiving part 42 as a space in which a current limiting element 29 constituting a ballast 31 is placed, and wires 43a, 43b are introduced into the side space 37 as a space different from the space in which the current limiting element 29 is placed. The wires 43a, 43b are further introduced into the slot 39 of the receiving body 33 and the wire insertion hole 38 and connect the ballast 31 and a discharge lamp 24 electrically.