Patent ID: 8606368

Claim:
An electrode system comprising: an electrode unit capable of switching at least a part of its shape between a curved shape and a stretched shape, wherein in the curved shape the electrode unit is wound around a predetermined linear tissue, and wherein in the stretched shape the electrode unit is flat; and a treatment tool that switches the shape of the at least a part of the electrode unit between the curved shape and the stretched shape, wherein the electrode unit includes: an insulating member formed in a sheet shape out of an elastic material; and an electrode that is disposed on a first surface which is an inside surface of a curvature when the insulating member has a curved shape and which applies a predetermined voltage, wherein the insulating member has the curved shape when an external force is not applied, wherein the treatment tool comprises a stretch mechanism that switches the curved shape of the electrode unit to the stretched shape, holds the stretched shape, and releases the holding, wherein the stretch mechanism comprises a stretch member formed of a material having a higher rigidity than that of the insulating member, and wherein the stretch member is capable of sliding relative to the insulating member to cause the insulating member to form the curved shape or the stretched shape.