An implant and a method of placing an implant indwelling are disclosed. The implant, to be placed indwelling in a living body, is inserted into a medical tube prior to being placed indwelling. The implant can include an implant main body which is flexible, is elongated, and is shorter than a length of the medical tube a guide portion which, at the time of insertion of the implant main body into the medical tube, is inserted into the medical tube prior to the implant main body and guides the implant main body and an interlock portion which interlock the implant main body and the guide portion to each other, the interlock being released after the implant main body is inserted into the medical tube.
