An implant assembly smoothly causes a folded implant to indwell a living body, and which can smoothly expand the implant without causing the implant to be displaced from a predetermined indwelling position when a filling material is injected. The implant assembly has the implant that is configured to be transformable from a folded and contracted state to an expanded state by the introduced filling material, and in which at least a portion of a surface thereof is covered with a covering material m whose friction coefficient increases by coming into contact with a body fluid, and guiding means for preventing the implant and the body fluid of the living body from coming into contact with each other inside the living body, and for guiding the implant to move to the indwelling position inside the living body.