Provided is a defect-closure device which is surely retainable in a predetermined position to close a passage-like defect in a living body. The device may have a free enlargement-contraction first member mounted so as to close an opening at the one end of the defect and a free enlargement-contraction second member having a protruded member, which extends from a joint part jointed to the first member, and protrudes from an opening at the other end in an axis direction of the defect. The first member is elastically contacted to the opening by elastically contacting a protrusion part of a second member to the inner surface of an edge of the opening.
