PROBLEM TO BE SOLVED: To provide an electrode assembly by which a part to be operated, which is attachable/detachable to/from an operating part, can be operated in the axial direction and around the axial direction by manipulating the operating part.SOLUTION: An electrode assembly 1 comprises: a part 10 to be operated, which has an electrode 12 and a first connection part 23 and is placed within a blood vessel and a long operating part 40 that has at its leading end a second detachable connection part 44 connected to the first connection part when the part to be operated is placed in a blood vessel. In the electrode assembly 1, when the first connection part and the second connection part are connected, the movement of the first connection part with respect to the second connection part is restricted in the axial direction C1 of the operating part and is also restricted to one side around the axis of the operating part.COPYRIGHT: (C)2015,JPO&INPIT【課題】操作部に対して着脱可能な被操作部を、操作部を操作することで軸線方向および軸線周りに操作可能な電極組立体を提供する。【解決手段】電極12および第一の連結部23を有し、血管内に留置される被操作部10と、血管内に被操作部を留置するときに、第一の連結部に着脱可能に連結される第二の連結部44を先端部に有する長尺の操作部40とを備える電極組立体1であって、第一の連結部と第二の連結部とを連結したときに、第二の連結部に対する第一の連結部の移動が、操作部の軸線C1方向に規制されるとともに、操作部の軸線周りの一方側に規制される。【選択図】図2