An object of the present invention is to provide a balloon ablation catheter wherein, even in cases where the catheter shaft is heated by high frequency, elongation of the catheter shaft can be suppressed to an extent where the elongation does not adversely affect use of the balloon ablation catheter, and the risk of a burn of the operator or the patient caused by the heating of the reinforcement wire in the catheter shaft can be largely reduced. The present invention provides a balloon ablation catheter comprising: a catheter shaft containing a reinforcement wire in a thick section a balloon provided at an end of the catheter shaft and a high-frequency electric current electrode arranged in the balloon which balloon ablation catheter satisfies L>t, wherein L represents the shortest distance from the surface of the reinforcement wire to the surface of the catheter shaft, and t represents the wall thickness of the thinnest portion of the balloon.
