An in-vivo indwelling instrument in which a stretch resistant member at a distal end part of a coil does not easily stray from the coil, and a delivering system for the in-vivo indwelling instrument is disclosed. An in-vivo indwelling instrument includes a coil formed by winding a wire, and a stretch resistant member that is placed in a lumen of the coil. In the view of the coil from a distal side, a part of the wire exists within a central region surrounded by a circle having a diameter of half a maximum outer diameter of the coil and having a center that is a middle point of the maximum outer diameter. The stretch resistant member and a connecting part which is the part of the wire are connected to each other.
