To provide a temperature adjusting system capable of efficiently performing cooling operation and heating operation in a wide scope of temperature adjustment using an inexpensive and safe refrigerant without causing noise.

This temperature adjusting system is provided with a refrigerant vessel 4 for sealing the refrigerant, a thermoelectric conversion unit 3 whose one end is thermally connected with an object whose temperature is adjusted and whose other end is thermally connected with the refrigerant vessel to cause phase change of the refrigerant in order to cool or heat the object whose temperature is adjusted, and a pressure adjusting means 8 for adjusting pressure in the refrigerant vessel.