PURPOSE: To provide a thermal louver device which simplifies a mechanism and reduces weight and a cost by a method wherein a shape memory alloy is used for at least e part of a blade, and the one end of the blade is disposed directly on a mounting base plate on which a heat generating device is mounted.

CONSTITUTION: A blade 1' is formed of a shape memory alloy, and heat from a heat generating device 3 is transmitted through a mounting base plate 2. A blade 1 is opened in a manner to be bent, and radiant radiation in a space from a mounting base plate surface on which high radiation rate treatment is applied is effected. By using a shape memory alloy being a temperature- sensitive metal for at least a part of the blade 1, the blade is mounted directly on the heat generating device 3 and the mounting base plate 2. Since the blade 1 itself additionally effects a drive function, this constitution simplifies a mechanism, improves thermal transfer and response since direct mounting is effected, and reduces a manufacturing cost and weight since a mechanism is simple.