An inner surface of a quartz crucible after being used is cleaned by an acid liquid, and an extraneous material adhered to its inner surface is removed. The inner surface after the extraneous material has been removed is heat treated at 1600° C. or more, and the inner surface where cristobalite formation occurs is recovered into an amorphous state. In this manner, the quartz crucible after being used for growing single crystal silicon is reproduced to a level equal to a new crucible.