VERY LOW TEMPERATURE COOLER

PROBLEM TO BE SOLVED: To make it possible to effectively cool material to be cooled to a predetermined temperature in a stable state by so providing a Peltier cooler as to bring the high-temperature end of the cooler into contact with the low- temperature side end of an outer cylinder, mounting the material to be cooled at the low-temperature side, measuring the temperature of the low-temperature end, and controlling the voltage to be applied to the cooler according to it output signal. SOLUTION: Material 2 to be cooled is mounted at the low-temperature side end 3a of an outer cylinder 3, i.e., the sidewall of a refrigerant chamber 9 via a Peltier cooler 31. The cooler 31 is so mounted in the state that the high-temperature end 31a of the cooler 31 is brought into contact with the low-temperature side end 3a of the cylinder 3 and with the low-temperature end 31b of the cooler 31 to mount the material 2 to be cooled. Temperature measuring means 32 is provided at the end 31b, and cooling temperature control means 33 for controlling the voltage applied to the cooler 31 by the signal is provided. The voltage is so applied that the end 31b becomes a predetermined temperature. That is, the material 2 to be cooled is cooled and mend by the end 31b of the cooler 31 controlled at a predetermined temperature.