With a view to simultaneously and precisely measuring the subtle air temperature distribution in the air atomosphere at multiple points on the wall surface of the room in the vicinity of the opening exposed to short wave radiation, the air temperature measuring system which actively sucks the air to be measured and which can suppress the amount of air suction required for a single-point measurement to approx. 0.96 cubic centimeter has been developed. In this system, the 20 mm chromel-alumel thermocouple with a diameter of 12 μm is suspended inside the 250 mm-long shielded cylinder with an inner diameter of 0.8 mm and outer diameter of 2.0 mm in such a way that thermocouple does not come into contact with the internal wall of the cylinder, then the shielded cylinder is connected via the miniature solenoid valve to the compact chamber box which can control the pressure to any required negative pressure with respect to the atmospheric pressure. The operating settings at which the amount of air suction was minimized were a suction drive pressure of 85 mmHg, and a solenoid valve release time of 50 ms.