PURPOSE: To maintain the specified temp. distribution within the horizontal plane of a single crystal and to enable the growth of the single crystal having good quality by providing the above device with functions capable of moving IR lamps and spheroid reflection surfaces in the major axis direction of this reflection mirror.

CONSTITUTION: A raw material rod 4 is first set in a raw material rod supporting section 7 and a seed crystal 8 in a grown crystal supporting section 6. The respective IR lamps 1 are respectively lighted and the voltages impressed on the IR lamps are gradually increased to dissolve the front end of the raw material rod 4. At this time, the raw material rod 4 is held static without applying rotation thereon. The voltages on the IR lamps are then dropped slightly as necessary to allow the front end of the raw material part to solidify when the front end of the raw material rod 4 dissolves. The raw material rod 4 is slowly rotated and the molten and solidified state thereof is observed. The positions of the respective spheroid reflection mirrors and the positions of the IR lamps are controlled in the major axis direction of the reflection mirrors 2 in such a manner that the molten part is homogeneously formed to a band shape.