Abstract: The present invention provides a stent delivery assembly including: a catheter including a shaft having a proximal end and a distal end, and a balloon provided closer to the proximal end than the distal end on the shaft; and a stent having a tubular shape, and coupled to the balloon to surround an outer circumferential surface of the balloon, wherein the balloon includes a main body having a first end and a second end, the stent is located to be biased towards the first end, such that the main body includes a preferential inflation region exposed to the outside between the second end and the stent, the main body is formed to extend with a diameter that is constant from the first end to the second end, and while the balloon is inflated, a portion of the stent close to the preferential inflation region is inflated in a tapered shape by a force caused when the preferential inflation region is preferentially inflated.