A process for manufacturing synthetic quartz glass involves feeding a quartz glass-forming raw material to a high-temperature gas zone within a chamber, converting the quartz glass-forming raw material into quartz soot, and forming synthetic quartz glass from the soot. A suspended soot-discharging gas which has been flow-straightened in a suspended soot discharging direction flows through the chamber in the vicinity of the high-temperature gas zone. This process keeps free suspended soot from settling onto the surface of the quartz ingot where fusion and growth take place, thereby preventing the formation of bubbles within the quartz glass under growth.