PURPOSE:To produce CdWO4 single crystal little in loss of material resulting from coloring, by making the atmosphere oxidative at the starting time of its pulling-up and weakening degree of oxidation from the midst thereof. CONSTITUTION:CdO and WO3 are introduced into a platinum crucible 1 so that the amount of CdO is regulated to about 1.03-1.3 times of the amount of WO3 and the mixture is heated with a high-frequency heating coil 2 and made to melt 3. Seed crystal 6 is brought into contact with the surface of the melt 3 for a raw material and pulled up while slowly rotating it and firstly a head part 7 is formed by growing crystal and furthermore a cylindrical part 8 is formed by increasing its diameter. In this pulling up, the head part 7 is formed by performing the pulling-up in the oxidative atmosphere (the atmosphere) at least at the starting time thereof and gaseous nitrogen is fed through a pipeline 9 from the time when the cylindrical part 8 is formed and the amount of gaseous nitrogen is increased in the proportion of about 1%/hr and degree of neutrality is enhanced by weakening degree of oxidation of the atmosphere. Thereby single crystal free from a crack which has the brown head part 7 and the transparent cylindrical part 8 can be obtained.
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