A living body lumen treatment system (10) includes a sheath (16) that internally has a receiving lumen (24), and a stent (12) that is received in a contraction state by the receiving lumen (24) and that expands by being exposed from the sheath (16). A first region (70) to which a drug is applied and a second region (72) to which the drug is not applied are set to be located on an outer surface of the stent (12) . The sheath (16) has a protrusion portion (60) protruding beyond an inner wall (26). In the stent (12), the second region (72) is brought into contact with and supported by the protrusion portion (60) so as not to bring the first region (70) into contact with the inner wall (26).