In order to perform balloon ablation and spot ablation by one ablation catheter without exchanging an ablation catheter body at the time of treatment by catheter ablation, an ablation catheter with a balloon is provided with a catheter shaft, a balloon which is mounted to the front end side in the longitudinal direction of the catheter shaft, a lumen which communicates with the balloon from the end face on the back end side in the abovementioned longitudinal direction, an in-balloon electrode and an in-balloon temperature sensor which are disposed in the balloon, and a front end electrode and a front end temperature sensor which are mounted in a front end region including the end face on the front end side in the abovementioned longitudinal direction.