A plurality of branch bars is provided on opposing sides of paired strut pieces connected by links in a strut to protrude from one towards the other side, and a plurality of ratchet teeth is formed on the side of the branch bars respectively. When a stent made of polymer material having a cylindrical constitution in which a plurality of struts is connected by links is deformed to enlarge its diameter, the paired struts are deformed to come near to each other, so that the branch bars overlap each other with the ratchet teeth formed thereon engaging with each other. As the effect of engagement of the ratchet teeth with each other, while deformation of the struts so as to enlarge the diameter of the stent is allowed, deformation so as to reduce the diameter of the stent is inhibited.
