Abstract: A knot-tying device with a rectangular card body made of rigid, buoyant material, including a retaining means for entraining separate leader lines in crossing diagonal relation, and a swivel disc cut from said card body, adapted to pivot in the card body. The swivel disc contains a bifurcated slot having closed ends extending to a single open end, receiving separate leader lines, for easy manipulation by fishermen with limited dexterity. The device is not costly to manufacture, small and easily stored, with few movable parts and withstands vigorous use. The operator swivels the disc, entrains the tag ends of the leader lines as well as the remaining lines in the card body, and the lines in the swivel disc slots. The operator rotates the swivel disc, forming the knot, then threads the tag ends through the gap in the knot, completing the knot-tying process.