A high-pressure discharge lamp includes: a quartz glass bulb; conductive elements; and a pair of electrodes. The conductive elements are airtightly sealed at sealing portions of the quartz glass bulb. Each electrode of the pair of electrodes is disposed so as to be opposite each other and connected to one of the conductive elements. The quartz glass bulb is formed as a single piece unit by using a synthetic quartz whose viscosity is about 10.sup.13 poise or more at about 1200.degree. C.