Disclosed is a stent device (1) in which a stent (3) that supports a blood vessel from inside is held by a stent cover member (4). Said stent device comprises a tube-shaped cartridge (2), a stent, and a stent cover member. The tube-shaped cartridge can expand and contract radially, but axial elongation thereof is restricted. The stent, which is formed into a tube shape from a bioabsorbable shape-memory polymer material, stores a shape which is equal or larger in diameter than the inside diameter of a blood vessel. In a contracted state, the stent is fitted around the outer surface of the tube-shaped cartridge. The stent cover member, which comprises an elastic bioabsorbable polymer material, is formed into a tube shape that has an inner diameter such that the stent is held in the aforementioned contracted state, and when the stent expands to the size stored therein, the stent cover member plastically deforms such that the stent is no longer held. As the tube-shaped cartridge expands radially, the stent expands along with the cover member, and when the tube-shaped cartridge contracts radially, the stent and the cover member separate from the tube-shaped cartridge.
