To provide a fluid circulation system and a temperature regulation system, capable of heating a fluid to a target temperature for a long time while reducing costs.

This fluid circulation system 3 of the temperature regulation system includes a fermentation chamber 30 receiving a fermentation heat source H, a liquid heater 41 for heating water, a liquid circulation pipe 45 for circulating the hot water heated by the liquid heater 41 to the temperature regulation device, a controller for heating the hot water roughly at a constant temperature by controlling the liquid heater 41, a spiral liquid heating section 62 for heating the fermentation heat source H from its outer side by utilizing heat of the hot water distributed by the liquid circulation pipe 45, and a pile 35 for heating the inside of the fermentation heat source H by geothermal heat.