Provided is a defect-closure device which has small area, and fixed position even in indwelling, and is surely retained in the predetermined position and has a simple configuration.A defect-closure device D for closing a passage-like defect O in a living body having: a free enlargement-contraction first member 1 mounted so as to close an opening Or at the one end of the defect O and a free enlargement-contraction second member 2 having a protruded member 7, which extends from a joint part 5 jointed to the first member 1, and protrudes from an opening Ol at the other end in an axis direction of the defect O, characterized in that the first member 1 is elastically contacted to the opening Or by elastically contacting the protrusion part 7 of the second member 2 to the inner surface of the opening edge of the opening O1.
