[Problem] To estimate the length of a stent implanted in a blood vessel after implantation of the stent. [Solution] A stent length estimation device 100 is provided with: an implantation start position specifying means for receiving, from a user, a designation of the implantation start position of an aneurism treatment stent in which a plurality of metal wires are braided in helical fashion on a three-dimensional blood vessel image representing the three-dimensional shape of a blood vessel, and specifying the implantation start position of the stent an implantation method specifying means for receiving a designation of the implantation direction of the stent from the user on the three-dimensional blood vessel image and specifying the implantation direction of the stent a stent specification specifying means for specifying as specifications of the stent the diameter of the expanded stent, the length of the expanded stent, the number of wires constituting the stent, and the pitch length of the wires constituting the stent after expansion of the stent and an implanted stent length calculating means for calculating the length of the implanted stent expanded in accordance with the blood vessel diameter, on the basis of the specifications of the stent specified by the stent specification specifying means and the blood vessel diameter of the blood vessel in the implantation direction specified by the implantation direction specifying means from the implantation start position specified by the implantation start position specifying means.La présente invention a pour objet destimer la longueur dun stent posé dans un vaisseau sanguin après la pose dudit stent. Linvention concerne un dispositif destimation de longueur de stent (100) comprenant : un moyen de spécification de position de début de pose destiné à recevoir dun utilisateur une désignation de la position de début de pose dun stent de traitement danévrisme dans lequel une pluralité de fils métalliques sont tressés de
