Quartz glass crucible and manufacturing method thereof

A manufacturing method of a quartz glass crucible according to a rotating mold method, the manufacturing method comprising:

• a step of forming a deposition layer of raw material quartz powder by depositing aluminum-added quartz powder and natural quartz powder in this order on an inner surface of a rotating mold;
• and
• a step of subjecting the deposition layer of the raw material quartz powder to arc melting from an inner side of the mold,
• wherein the step of subjecting the deposition layer of the raw material quartz powder to the arc melting includes
• a step of forming an inner transparent layer made of quartz glass with substantially no bubbles contained therein by strengthening a degree of decompression through a large number of vent holes provided in the inner surface of the mold at the time of start of the arc melting,
• a step of forming an opaque layer made of quartz glass containing a large number of minute bubbles by weakening the degree of decompression after forming the inner transparent layer, and
• a step of forming an outer transparent layer made of quartz glass with substantially no bubbles contained therein by strengthening the degree of decompression again after forming the opaque layer, and
• in the step of forming the outer transparent layer, the high-aluminum-content layer is formed by melting the aluminum-added quartz powder, and a timing at which the degree of decompression is strengthened again is controlled to form the outer transparent layer so as to cause a thickness of the outer transparent layer to be thicker than that of the high-aluminum-content layer.