PROBLEM TO BE SOLVED: To provide a device to be implanted in the lumen of a living body, which facilitates the formation of an endothelial cell surface layer after indwelling in the lumen of a living body.SOLUTION: The device 21 to be implanted in the lumen of a living body includes a member to be implanted in the lumen of a living body and a layer for inducing endothelial cells to be formed at least on a part of the surface of the member to be implanted in the lumen of a living body in contact with body fluid. The layer for inducing endothelial cells to be formed includes a compound having a plurality of thiol groups in a molecule.