A method for manufacturing a treatment tool is provided. The treatment tool includes: a function body having an elastic wire formed of a wire material made of a super-elastic material and having a predetermined shape, and a fixing portion having an insertion hole into which the elastic wire is insertable to house a proximal end portion of the elastic wire in the insertion hole； a tube portion configured to house the function body； and an operation unit configured to insert and remove the function body into and from the tube portion. The method includes: inserting the proximal end portion of the elastic wire into the insertion hole of the fixing portion； forming, at the proximal end portion of the elastic wire, an engagement portion for engaging with the insertion hole of the fixing portion； and fixing the proximal end portion of the elastic wire to the fixing portion.
