Abstract:
The present invention provides a process for producing a porous quartz glass base, which comprises hydrolyzing a silicon compound in an oxyhydrogen flame in a reaction furnace to generate and deposit fine silica particles on a starting member, thereby forming a porous quartz glass base, wherein a gas discharge pipe for discharging an unnecessary gas from the reaction furnace is heated. According to the present invention, fine silica particles can be prevented from adhering to a gas discharge pipe for discharging the unnecessary hydrogen chloride gas generated in producing a porous quartz glass base.