PROBLEM TO BE SOLVED: To provide a living body lumen blocking device capable of surely and safely blocking an optional part inside a living body lumen.SOLUTION: The living body lumen blocking device 1 is held inside the saccular part of an affected area expanded in a sac shape in the living body lumen, is used to prevent the rupture of the saccular part by blocking the saccular part, and includes: an embolization coil forming part 11 constituted of a cylindrical part 12 in which a wire 13 is knitted into a cylindrical shape whose diameter is freely expandable and contractible and a binding part 14 for binding the wire 13 at the end part of the cylindrical part 12 and a connection part 21 connected to and separated from a conveyance wire 301 for conveying the embolization coil forming part 11 to the saccular part and separating and indwelling it. To the embolization coil forming part 12, shape memory treatment is executed so as to be deformed into the shape of blocking the saccular part by being exposed to a living body temperature.
