It is intended to provide an in-vivo indwelling device, for example, an in-vivo indwelling device which has a high safety and a low risk of causing breakage of a coating layer formed on a surface of a stent during production or transportation of the stent, and moreover, when the stent is expanded during clinical use, or an in-vivo indwelling device with which a decrease in side effects of a remaining medicinal agent resulting from eliminating the medicinal agent as quickly as possible can be expected and which can carry a medicinal agent in a minimum amount necessary for suppressing restenosis. Such an object of the invention can be achieved by an in-vivo indwelling device which has an in-vivo indwelling device main body and a layer containing a medium-chain fatty acid triglyceride formed on at least a part of a surface of the in-vivo indwelling device main body and is put indwelling in a lumen in-vivo.
