To provide a heat circulation system capable of effectively reducing a loss of exergy by efficiently compressing gas having a relatively small flow rate.

After a supplied substance is heat-treated and gas is generated through a predetermined process (distilling or drying) using the heated substance, a temperature of the gas is increased by compressing the gas with a compressor 10 and heat due to the temperature increase is used as a heat source of a heating process of the substance. Thus, a heat circulation system can reduce energy consumption by increasing the temperature of the gas having a low exergy rate by compressing the same and utilizing the heat due to the temperature increase as the heat source of the heating process. By using a Roots dry pump as the compressor 10 which performs adiabatic compression to increase the temperature of the gas, the heat circulation system can efficiently compress the gas with reduced power consumption compared to a centrifugal rotary type or a screw type compressor even when a flow rate of the gas is small.