To provide a manufacturing method of inexpensive and highly pure synthetic quartz powder as a raw material of a quartz glass or filler for an IC sealing.

The manufacturing method of the inexpensive and high purity synthetic quartz powder is composed of (1) a process for producing fluorosilicate, (2) a process for mixing with a co-precipitating material and filtering the mixture, (3) a process for adjusting pH, (4) a process for gelating, (5) a process for freezing and thawing, (6) a process for drying, (7) a process for pulverizing and sieving, (8) a process for cleaning with purified water and (9) a process for firing. The fluorosilicate is inexpensive because waste quartz glass or a by-product is utilized and an apparatus is simplified because impurities are easily removed by adding the co-precipitating material and filtering the mixture. As a result the inexpensive and high pure synthetic quartz glass is manufactured.