[Problem] The purpose of the present invention is to provide an in vivo indwelling member which has loop-shape sites, and, when expanding through the strength thereof, curves in a complex manner in various directions into a shape that tends to expand inside of an aneurysm, etc., is not prone to becoming entangled and, even when converging together so as to overlap, untangles easily, and can maintain good operability and prevent tearing or damage to the aneurysm and to provide an in vivo indwelling member placement device provided with said in vivo indwelling member. [Solution] This member includes multiple loop-shape sites (R01, R11, R21-R23) which extend to at least one full circumvolution to form a loop, and said multiple loop-shaped sites are of at least two types having different loop lengths. From the distal side to the base side of the primary coil, the loop-shape sites are provided from loop-shaped sites of the type having a short loop length in order to the longer type loops at the base side. Only one loop-shaped site (R01) of the type having the shortest loop length is provided, and two or more loop-shaped sites (R21-R23) of the type having the longest loop length are provided.Le problème décrit par la présente invention est de fournir un élément à demeure in vivo qui comporte des sites en forme de boucle et qui, lors dune extension au moyen de sa résistance, se courbe dune manière complexe dans diverses directions dans une forme qui tend à sétendre à lintérieur dun anévrisme, etc., nest pas enclin à semmêler et, même lors dune convergence de manière à se chevaucher, se démêle facilement, et peut maintenir une bonne exploitabilité et empêcher le déchirement ou la rupture de lanévrisme et de fournir un dispositif de placement délément à demeure in vivo comprenant ledit élément à demeure in vivo. La solution selon linvention porte sur un élément qui comprend de multiples sites en forme de boucle (R01, R11, R21 à R23) qui sétendent sur au moins un tour comple
