(EN) An in-vivo indwelling tube having a high flap strength and smoothly passing through a duct such as an endoscope. A tubular member (104) having a proximal side and a distal side, and a proximal side of the tubular member (104) having a proximal base (106) and a distal free end (107). A proximal flap (105) and a distal flap (108) distal of the tubular member (104) having a distal base (109) and a proximal free end (110). , The tubular member (104) is radially outward of the tubular member (104) and more than the midpoint (P3) between the base (109) and the free end (110) of the distal flap (108). Provided closer to the distal side than the midpoint (P4) of the distal first support (10) provided on the distal side, the base (106) of the proximal flap (105), and the free end (107). And / or at least one of the proximal first supports (30).フラップの強度が高く、かつ内視鏡内等の管路の通過が円滑である生体内留置チューブを提供する。近位側と遠位側を有する筒状部材（１０４）と、筒状部材（１０４）の近位側に、近位側の基部（１０６）と遠位側の自由端（１０７）とを有する近位フラップ（１０５）と、筒状部材（１０４）の遠位側に、遠位側の基部（１０９）と近位側の自由端（１１０）とを有する遠位フラップ（１０８）とを含み、筒状部材（１０４）は、筒状部材（１０４）の径方向外方であって、遠位フラップ（１０８）の基部（１０９）と自由端（１１０）との中点（Ｐ３）よりも遠位側に設けられている遠位側第１支持体（１０）と近位フラップ（１０５）の基部（１０６）と自由端（１０７）との中点（Ｐ４）よりも近位側に設けられている近位側第１支持体（３０）の少なくともいずれか一方を有する。
