Method of manufacturing vitreous silica crucible

A method of manufacturing a vitreous silica crucible comprising:

• a silica powder supplying process of supplying a material silica powder into a mold for molding a vitreous silica crucible, to form a silica powder layer, and
• an arc fusing process of arc fusing the silica powder layer by arc discharge generated by carbon electrodes, wherein
• the arc fusing process includes processes of measuring a temperature of the silica powder layer with a radiation thermometer;
• obtaining a temperature at a local maximum point specific to the silica powder layer, said local maximum point appearing first in the arc fusing process where, after rising, the temperature starts to fall;
• then setting a temperature for controlling a vitreous silica fused state with reference to the temperature at the local maximum point used as a reference temperature;
• and controlling a vitreous silica fused state based on the set temperature,
• in the process of measuring a temperature of the silica powder layer, the temperature of the silica powder layer is measured where an observation line connecting the radiation thermometer and each temperature-measuring point on the silica powder layer is separated by 100 mm or more from the carbon electrodes, and
• the process of measuring a temperature of the silica powder layer includes measuring the temperature of the silica powder layer at a corner portion of the vitreous silica crucible.