This paper is concerned with the temperature distribution characteristics of an open type environment controlled growth facilities of Tohoku National Agricultural Experiment Station in Morioka. Placed in a field, the equipment has three controlled factors, i.e., air temperature, soil temperature and soil moisture. The upper part of a room, however, is opened to the outdoor so that the other environmental factors, e.g., air composition, sunshine, wind, etc., are free from the control. This is the first one designed as an open type equipment in Japan. The temperature distributions in the room were measured to observe the followings.
1) Range of temperature control in the experimental rooms is less than ±2°C from the outdoor temperature.
2) The regulation of the temperature of supply air from air ducts is disturbed by the sunshine.
3) Temperature distribution takes various patterns depending on the outdoor conditions. Its major disturbances are sunshine and outdoor wind.