Abstract: An electrode catheter includes a catheter shaft including a shaft main body enclosing a first lumen and a second lumen separated from each other, and a reinforcement layer embedded into the shaft main body, an electrode having a ring shape and mounted to an outer peripheral portion of the shaft main body, and a lead wire electrically conductive to the electrode and inserted into the first lumen. The reinforcement layer has conductivity and, inside the electrode, surrounds the second lumen without surrounding the first lumen.