A method for producing a single crystal from a crude melt contained in a quartz crucible placed in a furnace of an apparatus for producing a single crystal according to a Czochralski method, comprising: examining in advance a correlation between a molar concentration ratio of Al to Li, contained in a quartz raw material powder used for manufacturing the quartz crucible, a usage time of the quartz crucible, a ratio of a thickness of a devitrification part to a thickness of the quartz crucible at the time of use, and occurrence or non-occurrence of melt leakage attributable to the devitrification part; setting a range the ratio of the thickness of the devitrification part to the thickness of the quartz crucible used for growing the single crystal so as not to generate any melt leakage attributable to the devitrification part; and determining a maximum usage time for the quartz crucible gel according to the molar concentration ratio of Al to Li contained in the quartz raw material powder used for manufacturing the quartz crucible so as to fall within the set range of the ratio based on the correlation; and growing the single crystal using the quartz crucible in the range of the maximum use time.
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