The present invention provides a quartz glass burner that can enhance the heating power of flame working without unnecessarily increasing the flow of combustion gas and improve the deposition efficiency on depositing glass particles onto a porous glass preform. The quartz glass burner has a large diameter outer tube, and a plurality of small diameter inner tubes enclosed in the outer tube, and a tip of the outer tube has a port defining member defining the outer shape of a combustion gas ejecting port that ejects combustion gas, and the port defining member protrudes from the inner circumference of the outer tube towards the center axis so as to block the outermost area including areas between the outer circumferences of a plurality of inner tubes forming the inner tube row and the inner circumference of the outer tube of the combustion gas flow path.