To measure and control the surface temperature or surface temperature distribution of an optical module accurately in the environment temperature test of the optical module.

The temperature at a specified site on the surface of an optical module 10 is measured with a radiation thermometer 40, and a temperature variable section 30 in contact with the optical module 10 is heated and cooled based on the measured temperature, thus controlling the site to specific temperature. Even in test specifications for defining optical-module surface temperature as the test temperature, the surface of the optical module is measured and controlled directly, thus achieving an accurate temperature sequence.