Abstract: An easily foldable closure device for transcatheter operations, comprises: a flat closure member including a closure membrane and a frame for fimbriating a periphery of the membrane; a fixing member for fixing the closure member to a tissue surrounding a defect aperture; and a connecting member fixed at one end to the fixing member and at the other end to the closure member for holding them in close proximity to one another. The frame, fixing member and connecting member are respectively made of the same or different shape-memory alloys with a shape recovery temperature of 30 to 37° C.