A knot tying device for tying knots including an inner rod having a longitudinal slot extending between the two open ends from an outer diameter to a hollow center. An hollow cylinder is disposed on the inner rod and has a longitudinal slot extending between the two open ends from an outer diameter to a hollow center. A cord clamp is formed between the hollow cylinder and the inner rod, and secures a cord to an end of the outer hollow cylinder. A cord winding cylinder is rotatably disposed on the inner cylinder and has a cord catch and a longitudinal slot extending between the two open ends from an outer diameter to a hollow center. The cord catch can catch a cord secured by the cord clamp and can wind the cord around the outer hollow cylinder.