To reduce the dispersion of quality, to enable miniaturization, further, to reduce power consumption and to decrease running costs as well by successively performing test operation while previously fixing the temperature of heat sensor to be tested, placing it on a pedestal and blowing hot air from the downside.

This device has a test stage 4 constituted by combining a pedestal 2 for placing a heat sensor K with an air blowing and supplying means 3 composed of a spot heater for blowing the temperature and quantity controlled hot air from the downside of pedestal 2. The air blowing and supplying means 3 is composed of a cylindrical heater providing a discharge port 3c at the upper end of main body 3b incorporating a heater and having an air supply port 3a to supply quantity controlled air. Then, the test operation is successively performed while previously fixing the temperature of heat sensor K to be tested, placing it on the pedestal 2 later and blowing hot air from the air blowing and supplying means 3 from its downside. Because of such a thermal characteristic testing method, a heat loss is reduced and dispersion is decreased as well.