To provide a cylindrical medical indwelling device that is introduced in a luminal organ and sufficiently resists the action of reducing the diameter after being increased in diameter and made to indwell, and is simple in design and manufacture.SOLUTION: An indwelling device is configured in a cylindrical shape having a mesh structure where multiple struts 2 are connected by connecting means of ribs 3, etc. Each strut 2 comprises: bistable structure portions 11, 12a, 12b being made by the combination of multiple strut sides for resisting the action to the contracting direction and holding an extension state in a stable state after being jumped in a process of extension and deformed through buckling deformation； and strut sides 13, 14 connected on both sides in the circumferential direction of the indwelling device in the bistable structure, respectively, and extending to the circumferential direction. The strut sides are made to become a shape structure extending in the circumferential direction are not on the same line in the circumferential direction and displaced in an axial direction of the indwelling device, and thereby an enlarged diameter state of the indwelling device is held.SELECTED DRAWING: Figure 2【課題】管腔臓器内に導入され拡径して留置された後の縮径させる作用に対して十分に抗するものとし、設計・製作を簡易な円筒形状の医療用留置器具を提供する。【解決手段】留置器具は、複数のストラット２ががリブ３等の連結手段で連結されて網目構造を有する円筒形状に構成される。各ストラット２はその伸張の過程で飛び移り座屈変形を経て変形した後の安定状態で収縮する方向への作用に抗し伸張状態を保持する複数のストラット辺の組合せによる双安定構造の部分１１、１２ａ、１２ｂと、双安定構造における留置器具の周方向の両側にそれぞれ連結された周方向に延びるストラット辺１３、１４とからなり、周方向に延びるストラット辺が周方向に同一線上になく留置器具の軸方向にずれて配設される形状構造になるようにし、留置器具の拡径状態を保持する。【選択図】図２
