An extracorporeal circulation device used for an isolation temperature control method to maintain an object at a preset temperature, comprising (A) a replenisher liquid supply unit which meters a temperature-controlled replenisher liquid for injecting into a blood vessel, (B) a blood concentrating unit which meters the replenisher liquid-diluted blood for guiding from the blood vessel and which concentrates the guided diluted blood, and (C) a blood supply unit which meters the concentrated blood for injecting into the blood vessel while a blood temperature is controlled, wherein the blood concentrating unit has a diluted blood temperature sensor for measuring a guided diluted blood temperature, and the replenisher liquid supply unit has a means for controlling a supplying replenisher liquid temperature based on the difference between a measured diluted blood temperature and a preset temperature of the object. |