SHORT ARC TYPE DISCHARGE LAMP

PROBLEM TO BE SOLVED: To provide a short arc type discharge lamp with reduced risk of rupture of a lamp.SOLUTION: A short arc type discharge lamp comprises: a spherical part; and two seal pipe parts opposed to each other along an axial line passing through the spherical part. In each seal pipe part, when maximum thickness of each seal pipe part is thickness t(mm), length from a position C at which a luminous tube sealing body spherical part side end of a first seal member is in contact with the seal pipe part toward the luminous tube sealing body spherical part is L1(mm), length from the position C toward a mouth piece is L2(mm), length from a position D contacting a face (center face) orthogonal to a center axial line direction of the seal tube part and passing through a center of a first collector disc toward the luminous tube sealing body is L3(mm), and length from the position D toward the mouth piece is L4(mm), 3≤t≤8, 5≤L1≤20, 5≤L2≤15, 5≤L3≤15, and 5≤L4≤20 are satisfied. Furthermore, a concentration of an OH group is within a range of 10 ppm to 200 ppm.