Method for manufacturing stent delivery system and stent delivery system

A stent delivery system comprising:

• an inner tube;
• an outer tube configured to be movable forward and rearward relative to the inner tube, the outer tube including a first outer tube, a second outer tube on a proximal end side of the first outer tube, and a third outer tube on a proximal end side of the second outer tube;
• a self-expanding stent disposed between the inner tube and the outer tube;
• a pair of operation wires configured to operate the forward and rearward movement by the outer tube, and wherein the self-expanding stent and the pair of operation wires are disposed separately along an axis of the stent delivery system;
• the first outer tube of the outer tube including a first tube shaped body, a second tube shaped body disposed at an outer peripheral side of the first tube shaped body, and a retaining member configured to retain the pair of the operation wires between the first tube shaped body and the second tube shaped body;
• the first tube shaped body having a cross-sectional shape in which two parts disposed with the pair of the operation wires are brought closer to each other inwardly in a radial direction than other parts in a circumferential direction of the first tube shaped body;
• the first tube shaped body having an axially orthogonal elliptical cross-sectional shape;
• the second tube shaped body having an axially orthogonal circular cross-sectional shape, the self-expanding stent configured to be disposed in the second tube shaped body;
• the third tube shaped body having an axially orthogonal elliptical cross-sectional shape;
• a fourth tube shaped body having an axial orthogonal elliptical cross-sectional shape, the fourth tube shaped body being provided at an outer peripheral side of the third tube shaped body and is disposed with the pair of the operation wires at an inner peripheral side of the fourth tube shaped body;
• the retaining member being disposed in a space formed between an outer peripheral surface of the first tube shaped body and an inner peripheral surface of the second tube shaped body and on a shorter axis of the first tube shaped body having the axially orthogonal elliptical cross-sectional shape and a shorter axis of the third tube shaped body having the axial orthogonal elliptical cross-sectional shape;
• wherein the pair of operation wires are disposed on the shorter axis of the axially elliptical cross-sectional shape of the first tube shaped body;
• and
• wherein the third outer tube includes a distal-side tube and a proximal-side tube, the proximal-side tube being fixed to a proximal end side of the distal-side tube, the proximal-side tube includes a wire insertion tube arranged in a lumen of the proximal-end side tube, the wire insertion tube including a wire lumen configured to receive the pair of operation wires and a base portion shaft wire, and wherein the pair of operation wires and the base portion shaft wire are located inside of the wire lumen in a distal end of the wire insertion tube, and wherein the distal end of the wire insertion tube is in the lumen of the proximal-end side tube.