The present invention relates to a process for production of a synthetic quartz glass having a fluorine concentration of 1,000 mass ppm or more, the process comprising: (a) a step of depositing and growing quartz glass fine particles obtained by flame hydrolysis of a glass forming raw material onto a substrate, to thereby form a porous glass body; (b) a step of keeping the porous glass body in a reaction vessel that is filled with elemental fluorine (F2) or a mixed gas comprising elemental fluorine (F2) diluted with an inert gas and contains a solid metal fluoride, to thereby obtain a fluorine-containing porous glass body; and (c) a step of heating the fluorine-containing porous glass body to a transparent vitrification temperature, to thereby obtain a fluorine-containing transparent glass body.