A suture-fixing system includes: an outer sheath which is insertable into a body a suture-fixing tool having a first opening and a second opening configured to communicate with each other, the suture-fixing tool disposed at a distal end of the outer sheath a lead-in tool which is inserted into the suture-fixing tool and is movable inside the outer sheath and an engaging portion which is disposed at a distal end of the lead-in tool and extends in a loop shape or a U-shape from one of the first opening and the second opening which is located more distally than another wherein both the suture-fixing tool and the engaging portion, or only the engaging portion is capable of forming an encircled area through which a portion of a surgical suture locked to a tissue can pass, using a medical instrument which sutures tissue with the surgical suture, and the engaging portion moves the portion of the surgical suture toward more proximal position than a proximal opening of the suture-fixing tool by the lead-in tool being moved to a more proximal position of the outer sheath.
