Patent ID: 8066731

Claim:
A treatment device, comprising: a catheter having a lumen that is opened to a distal end of the catheter; a wire passing through the lumen so that the wire is inserted into or retracted from the lumen and having an end portion which is formed in a tapered shape; and a piece that is fitted to the end portion of the wire and that has a piece body in which a maximum width when the piece is protruded out from the distal end of the catheter is set larger than the diameter of the lumen and has a base portion which covers a periphery of the end portion, wherein the end portion has a diameter smaller than an immediately adjacent portion of the wire; and the piece body has a curved surface shape that distributes concentration of pressure acting on tissues, a maximum width of the piece body when the piece is protruded out from a distal end of the catheter being set larger than a diameter of the lumen, a cross-sectional area at the maximum width portion of the piece body in a direction perpendicular to an axial line of the catheter being set smaller than a section area of the lumen in a direction perpendicular to the axial line of the lumen, and when the wire is pulled in toward the catheter, the maximum width portion being deformed so that the piece is housed in the lumen.