Provided is a connection structure for connecting a treatment component to an operating wire using a coupling member. The treatment component has a rod-shaped proximal end. The coupling member includes a first hole portion into which the proximal end is configured to be inserted on one end, and a second hole portion into which the operating wire is configured to be inserted on the other end. With the proximal end inserted into the first hole portion, the proximal end and the coupling member are joined by swaging and plastically deforming part of the first hole portion. With the operating wire inserted into the second hole portion, the operating wire and the coupling member are joined by swaging and plastically deforming part of the second hole portion. Joint strength between the proximal end and the coupling member is higher than joint strength between the operating wire and the coupling member.
