Stent delivery system and endoscope system

A stent delivery system comprising:

• a guide catheter that can be inserted into a channel of an endoscope;
• a stent formed in a tubular shape and provided with a first passage into which the guide catheter can be inserted;
• and
• a pusher catheter formed in a tubular shape, provided with a second passage into which the guide catheter can be inserted, and disposed in a proximal end side relative to the stent,
• the guide catheter having, in a state in which the guide catheter is inserted into the stent and the pusher catheter,
• a guide catheter tip portion protruding to a distal end side further than the stent,
• a guide catheter body disposed inside the stent and the pusher catheter,
• wherein a portion of the guide catheter inserted into the stent is defined as a stent mounted region,
• a portion of the guide catheter inserted into the pusher catheter is defined as a pusher mounted region,
• the stent has flexural rigidity equal to or lower than that of the guide catheter body, and
• the stent mounted region has flexural rigidity equal to or lower than that of the pusher mounted region.