PURPOSE: To obtain a single crystal which is small in transition density in the crystal and is long-sized by controlling the height of a heat retaining cylinder under specific conditions at the time of growing the single crystal by an LEC method.

CONSTITUTION: The height of the heat retaining cylinder is adjusted in the following manner in the growth of the single crystal by the LEC method. Namely, the top end of the inside wall of the heat retaining cylinder 3 is so set as to be made higher than the conical plane (shown by a dotted line) regulated by the solid-liquid boundary between the raw material melt 5 in a crucible and a pulled up crystal and the top end of the crucible 10 at the time of starting the growth of the straight cylindrical part of the crystal 4 and to be made lower than the conical plane regulated by the solid-liquid boundary between the raw material melt in the crucible and the pulled up crystal and the top end of the crucible at the time of ending the growth of the straight cylindrical part of the crystal.