A self-ligating orthodontic bracket assembly comprising: a bracket body having an attachment surface and a slot, the attachment surface configured to be adhered to a tooth surface, the slot having an open form to enable a placement of a wire along a teeth alignment direction; a ligation slide installed movably on the bracket body to enable a selective opening/closing operation of the slot; and a binding part for restraining the ligation slide to prevent the ligation slide from becoming detached from the bracket body, wherein the binding part comprises a pin member and a retainer, pin member provided on the bracket body to be arranged in a movement zone of the ligation slide, the retainer provided on the ligation slide in a manner enabling a complementary fastening/detaching action with the pin member, a ligating and releasing operation is selectively achieved for the wire inserted in the slot by the complementary fastening/detaching action of the retainer and the pin member according to a movement of the ligation slide, the retainer is installed on a lower surface of the ligation slide facing the bracket body, the retainer is made with a flat spring element formed as a snap ring to enable the complementary fastening/detaching action while being elastically deformed by the pin member according to a movement of the ligation slide, and the retainer comprises a disk part, pair of floating plates, and a pair of shock-absorbing elastic ribs, the disk part having a circular hole formed in a body made of a flat elastic piece, the pair of floating plates protruding and extending from the disk part such that a slit hole continuing from an open one side of the circular hole has a shape of a keyseat, the pair of shock-absorbing elastic ribs each formed with an arced elongated hole formed as a recessed indentation connecting to the other side of the circular hole and with a vane protruding inward from a boundary portion between the circular hole and the arced elongated hole. a bracket body having an attachment surface and a slot, the attachment surface configured to be adhered to a tooth surface, the slot having an open form to enable a placement of a wire along a teeth alignment direction; a ligation slide installed movably on the bracket body to enable a selective opening/closing operation of the slot; and a binding part for restraining the ligation slide to prevent the ligation slide from becoming detached from the bracket body, wherein the binding part comprises a pin member and a retainer, pin member provided on the bracket body to be arranged in a movement zone of the ligation slide, the retainer provided on the ligation slide in a manner enabling a complementary fastening/detaching action with the pin member, a ligating and releasing operation is selectively achieved for the wire inserted in the slot by the complementary fastening/detaching action of the retainer and the pin member according to a movement of the ligation slide, the retainer is installed on a lower surface of the ligation slide facing the bracket body, the retainer is made with a flat spring element formed as a snap ring to enable the complementary fastening/detaching action while being elastically deformed by the pin member according to a movement of the ligation slide, and the retainer comprises a disk part, pair of floating plates, and a pair of shock-absorbing elastic ribs, the disk part having a circular hole formed in a body made of a flat elastic piece, the pair of floating plates protruding and extending from the disk part such that a slit hole continuing from an open one side of the circular hole has a shape of a keyseat, the pair of shock-absorbing elastic ribs each formed with an arced elongated hole formed as a recessed indentation connecting to the other side of the circular hole and with a vane protruding inward from a boundary portion between the circular hole and the arced elongated hole.