A stent delivery system includes a self-expanding stent, an inner tube body which has a guide wire lumen, and a sheath which has the stent contained within the tip section thereof. The stent can be discharged by moving the sheath to the base end side relative to the inner tube body. The inner tube body is provided at a position within the base end section of the stent and is provided with an elastic member for pressing the stent in the direction to the sheath. The stent is gripped by the elastic member and the sheath and is adapted to be slidable relative to the sheath.