High-frequency knife

A high-frequency knife, comprising:

• an electrically insulating flexible sheath having a distal end and a proximal end;
• an operation member having a distal end and a proximal end, and movable in an axial direction in the sheath;
• an electrode part provided on the distal end of the operation member, at least a part of the electrode part being axially projected from and retracted in the distal end of the sheath, the electrode part having a rod electrode part extending in the axial direction of the sheath and a plate electrode part disposed on a distal end of the rod electrode part, the plate electrode part including a plane surface part extending in a direction crossing the axis direction of the sheath,
• a handheld operation section provided on the proximal end of the sheath, the operation section having a slider part which moves the operation member in the axial direction of the sheath;
• and
• a connector part provided on the slider part, and having an internal end portion and an external end portion, the external end portion being electrically connected with a cord communicating with a high-frequency generating source, and the internal end portion being electrically connected with the electrode part through the operation member.