The stirring efficiency of a heating liquid which is supplied to the balloon of a balloon-equipped ablation catheter is increased to quickly uniformize the surface temperature of the balloon, and air is prevented from remaining in the balloon-equipped ablation catheter to enhance the safety of treatment which uses the balloon-equipped ablation catheter. A shaft for a balloon-equipped ablation catheter, consisting of a single pipe, wherein the shaft has two lumens which communicate from the distal end to the proximal end of the shaft, a first lumen being a guide wire passage lumen which is provided in order to allow a guide wire to pass therethrough, the second lumen being a liquid supply lumen which is provided in order to supply liquid to the inside of the balloon of the balloon-equipped ablation catheter.
