Abstract: An in vivo temperature control system including a catheter insertable into a living body; a temperature sensor that can measure the temperature in the living body; a liquid storage section that stores a liquid; a pump that supplies the liquid from the liquid storage section to the catheter; and a control section that controls driving of the pump; wherein the control section calculates a difference obtained by subtracting an integrated amount of the liquid sucked inside of the catheter from an integrated amount of the liquid released outside of the catheter, and allows the pump to operate and suck the liquid into the catheter when the difference exceeds a preset threshold, and then stop the driving of the pump when the difference reaches the preset threshold or less.

Abstract: An in vivo temperature control system includes a catheter insertable into a biological lumen; two or more temperature sensors placed such that they can measure a temperature distribution in a longitudinal direction of the biological lumen; a liquid storage section that stores a liquid; and a control section that estimates a spatial change in the biological lumen based on a temperature change before and after the liquid in the liquid storage section is released outwardly through the catheter, wherein the temperature change is measured by each of two or more temperature sensors.