Production Method of Quartz Glass

(canceled)

A manufacturing method of manufacturing quartz glass, said method comprising:

• depositing soot generated by flame hydrolysis of a raw material gas to a starting member, while the starting member is raised and rotated, to form a soot deposition member that includes (i) an effective portion having a substantially constant outer diameter, the effective portion to become a material of a glass product, (ii) an upper ineffective portion formed at an upper end of the effective portion, and (iii) a lower ineffective portion formed at a lower end of the effective portion, each of the ineffective portions having an outer diameter changing in a tapering form,
• wherein said depositing comprises forming the lower ineffective portion while decreasing a peripheral speed of a surface of the starting member to a predetermined final peripheral speed in a ratio of 1.3 m/minute or below per second during a period after the effective portion is formed and until the starting member and the soot deposition member stop rotating.