It is intended to provide a stent having little or no risk of the breakage of a coating layer that is formed on the stent surface in the course of producing or transporting the stent or during the step of expanding the stent in clinical use. In other words, a stent to be implanted in a lumen in the living body wherein a layer including a physiologically active substance, a biodegradable polymer and a citric acid ester employed as a plasticizer is formed at least a part of the surface of the stent body.