Stent delivery system

A stent delivery system comprising:

• a guide catheter capable of being inserted into a channel of an endoscope;
• a stent formed in a tube shape and into which the guide catheter is capable of being inserted;
• and
• a pusher catheter formed in a tube shape and into which the guide catheter is capable of being inserted, the pusher catheter being disposed nearer to a proximal end side than the stent,
• wherein the pusher catheter includes:
• a diameter expansion-suppressing part provided at a distal end part of the pusher catheter and having an inner diameter the same as an inner diameter of the stent;
• and
• an intermediate part provided at a proximal end side of the diameter expansion-suppressing part and having a bending stiffness less than a bending stiffness of the diameter expansion-suppressing part, and
• wherein, when the stent is pushed toward a distal end side by pushing the intermediate part of the pusher catheter toward the distal end side and causing a distal end part of the diameter expansion-suppressing part to come into contact with a proximal end part of the stent, the diameter expansion-suppressing part prevents an inner diameter of the distal end part of the pusher catheter from expanding.