Provided is an ablation catheter system with a balloon which can improve the effect of therapy by ablation by eliminating variation in the surface temperature of a balloon in the ablation catheter with a balloon which cauterizes the tissue. An ablation catheter system with a balloon comprising a catheter shaft, a balloon fixed to the catheter shaft, a lumen which penetrates the catheter shaft in the direction of the long axis and communicates with the interior of the balloon, a heating electrode arranged in the balloon, a heating device which applies electrical energy to the heating electrode, and a vibration imparting device which imparts a vibration to the heating liquid by periodically repeating suction and ejection of the heating liquid from the lumen. Also provided is a stirring method for stirring the heating liquid by vibration wherein the vibration is imparted in such a manner that the value obtained by dividing the volume of the heating liquid being ejected toward the balloon by single ejection by the expansion volume of the balloon and then multiplying the quotient by 100 becomes 2-9.
