PROBLEM TO BE SOLVED: To provide an in vivo indwelling object excellent in maintenance of antithrombotic properties, in particular an artificial blood vessel with a small diameter.SOLUTION: An in vivo indwelling object includes: a substrate layer of which at least the surface is composed of expanded polytetrafluoroethylene (ePTFE) a compound having a plurality of thiol groups in the molecule and supported on at least a part of the substrate layer and a biocompatible layer composed of a copolymer of a monomer having a reactive functional group in the molecule and a (meth)acrylate and covering the compound having the plurality of thiol groups in the molecule, and has antithrombotic properties, in which the compound having thiol groups is made to be supported on the substrate layer by irradiation of ionized gas plasma, and the biocompatible layer is bonded to the substrate layer by making the compound having thiol groups and the copolymer react with each other.COPYRIGHT: (C)2015,JPO&INPIT【課題】抗血栓維持性に優れる体内留置物、特に小口径の人工血管を提供する。【解決手段】少なくとも表面が延伸ポリテトラフルオロエチレン(ePTFE)からなる基材層と、該基材層の少なくとも一部に担持された分子内に複数のチオール基を有する化合物と、該分子内に複数のチオール基を有する化合物を覆う、反応性官能基を分子内に有する単量体と(メタ)アクリル酸エステルとの共重合体からなる生体適合性層と、を備え、該チオール基を有する化合物がイオン化ガスプラズマを照射することにより基材層に担持されており、かつ該チオール基を有する化合物と、該共重合体とを反応させることで生体適合性層が基材層に結合している、抗血栓性を有する体内留置物。【選択図】なし