A stent delivery system 1 for supplying a stent to a body cavity which includes an endoscope 6 that has an insertion portion 5 with a curvature portion 3 disposed at the distal end thereof, a sheath 7 that is disposed with the insertion portion 5 inserted in the inside thereof and a stent 2 placed on the outer surface of the distal end side thereof; and a regulating portion 8 that regulates the relative movement of the stent 2 to the proximal end side of the sheath 7, with the sheath 7 formed of a length that allows the distal end of the insertion portion 5 that is inserted in the sheath 7 to protrude from the distal end of the sheath 7. In accordance with the present invention, it is possible to provide a stent delivery system that can place a stent by endoscope observation without the need of excessive diametrical contraction or additional expansion of the stent.