An arc tube for a discharge lamp device comprises: a cylindrical glass tube made of glass, having linear extension portions, each having an opening portion at an end, and a spherically swollen portion formed between the linear extension portions; and electrode assemblies inserted in the respective linear extension portions, wherein neck portions are formed in boundaries between the spherically swollen portion and the linear extension portions so that the glass in each of the linear extension portions side is prevented from flowing into the inside of the spherically swollen portion when the linear extension portions are pinch-sealed.