The present invention includes a linear material used for a stent implanted in a blood vessel such as the coronary artery, and a blood vessel stent employing this linear material. The linear material is formed of a biodegradable polymer poly-(L-lactic acid), and has a crystallinity, as measured by differential calorimetry, of 15 to 60%. The linear material is a monofilament having a diameter of 0.08 mm to 0.30 mm. This monofilament is shaped to a tubular structure used as the blood vessel stent.
