A stent comprising a tubular stent matrix of which diameter is extendable and a flexible polymer layer covering the stent matrix. The polymer layer is closely attached to and covers the entire surface of the stent matrix. Since the flexible polymer layer closely covers the entire surface of the stent matrix not only the outer periphery of the stent matrix, the stent has no problem of causing allergic to metal, stimulus of tissues due to metal, and rust development. Since the inner periphery of the stent is a flat and smooth surface covered by the polymer layer without convexes and concaves, the formation of thrombus can be inhibited well. There is no problem of drift between the polymer layer and the stent matrix, thereby maintaining the positional relationship between the stent matrix and the polymer layer before and after the expansion of the stent.
