Disclosed is a stent device wherein a stent (2), which, upon being implanted in a blood vessel, expands and supports said blood vessel from the inside, is held in a contracted state by a stent cover member (3). The stent is formed into a tube shape from a bioabsorbable shape-memory polylactic acid (PLA) and stores a shape of a size such that upon being implanted in a blood vessel, the stent can support said blood vessel from the inside. The stent is inserted, on the balloon (12) of a balloon catheter (11), into the blood vessel while being held in a contracted state by the cover member. The cover member is formed, from an elastic bioabsorbable polymer material, into a tube shape of a size such that the inner diameter thereof holds the stent in the contracted state. When the stent expands to the size stored therein, the cover member plastically deforms such that the stent is no longer held. After being implanted in the blood vessel, the stent and the stent cover member disappear in the blood vessel.
