In order to sufficiently cauterize a target site existing in a deep portion of a cardiac muscle tissue even in the case where the fat layer attached to an epicardium is thick or where the cardiac muscle is thickened due to cardiac hypertrophy and the like, provided is an ablation catheter comprising: an elongated catheter main body; an electrode for ablation placed in a leading end part of the catheter main body; and an optical fiber that is placed along a longitudinal direction of the catheter main body, includes an emission end formed on a leading end surface of the catheter main body, and emits a laser beam guided therethrough from the emission end.