The present invention has the objective of providing an ablation catheter with balloon which achieves together a decrease in diameter of the balloon at balloon contraction time and increase in reliability of a thermocouple temperature sensor, and simultaneously is resistant to being affected by a heating liquid delivered to within the balloon and is capable of controlling balloon surface temperature with high precision. The present invention is an ablation catheter with balloon which is provided with a shaft having a lumen, a balloon such that the lumen is in communication with the interior of the balloon, and a high-frequency current-delivering electrode which is formed by winding a high-frequency power supply lead wire into a coil around the shaft while sandwiching a temperature sensor lead wire between the high-frequency power supply lead wire and the shaft so that the temperature sensor lead wire is fixed along the long axis direction of the shaft. A thermocouple temperature sensor is formed at a point where the high-frequency power supply lead wire and the temperature sensor lead wire, which configure the high-frequency current-delivering electrode, first come into tactile contact as viewed from the rear end side in the long axis direction.La présente invention concerne un cathéter dablation avec un ballonnet qui permet à la fois une réduction du diamètre du ballonnet au moment de la contraction du ballonnet et une plus grande fiabilité dun capteur de température thermocouple, et qui, en même temps, nest pas affecté par un liquide chaud délivré à lintérieur du ballonnet et est capable de réguler avec une grande précision la température de surface du ballonnet. La présente invention concerne un cathéter dablation avec un ballonnet doté dune tige ayant une lumière, un ballonnet tel que la lumière se trouve en communication avec lintérieur du ballonnet, et une électrode de délivrance de courant haute fréquence qui est formé par enroulement dun fil métallique dalim
