PURPOSE: To reduce total area of heat radiation board by driving a thermal drive cooler through utilization of high temperature discharge heat.

CONSTITUTION: In a space heat controller, a heat receiver 3 incorporating a regenerator and a thermoelectric converter 2 is arranged at the focus position of a light collecting mirror 1, and the heat receiving side of a thermal driving cooler 5 is coupled through a hydraulic loop 4 with the heat discharge side (high temperature heat discharge source) of the thermoelectric converter 2. The cooler 5 is coupled through a heat bus loop 6 with a cold plate 8 and through a heat discharge loop 9 with a heat radiation board 10. By such arrangement, temperature of the heat discharge board can be made higher than the temperature of the heat bus.