Disclosed is an intracardiac defibrillation catheter which can feed a necessary and sufficient electric energy reliably for a defibrillation so that the catheter can perform the defibrillation without burning the body surface of a patient. The defibrillation catheter comprises an insulating tube member (10) having a multi-lumen structure, a handle (20) connected to the base end of the tube member (10), a first DC electrode group (31G) mounted in the tip region of the tube member (10), a second DC electrode group (32G) mounted in the tube member (10) but apart to the base side from the first DC electrode group (31G), a first lead wire group (41G) having lead wires (41) connected individually with the electrodes composing the first DC electrode group (31G), and a second lead wire group (42G) having lead wires (42) connected individually with the electrodes composing the second DC electrode group (32G). The first lead wire group (41G) and the second lead wire group (42G) extend in different lumens (11 and 12) of the tube member (10).
