| 摘要 |
According to embodiments, a distance between a center of a light-emitting portion and a reference protrusion is changeable by selecting either one of a first holding position or a second holding position with respect to a common one-type burner. A holding piece is inclined to a first surface side at a first angle with respect to a diametral direction of a ring portion and a tip portion of the holding piece protrudes to the first surface side to hold an outer tube at the first holding position. And the holding piece is inclined to a second surface side at a second angle that is smaller than the first angle with respect to the diametral direction of the ring portion and the tip portion of the holding piece protrudes to the second surface side to hold the outer tube at the second holding position. |
