Disclosed herein is a method of manufacturing a master link which connects ends of track chains of an endless track to each other. More particularly, the present invention relates to a method of manufacturing a master link which includes a pair of partial link units that are separably coupled to each other, and which can markedly enhance the degree of precision in machining the partial link units and the quality of the product. The method includes forming a wire-cutting reference hole at a predetermined position in the master link so that a wire is inserted into the wire-cutting reference hole, and forming the first and second partial link units by wire-cutting after inserting the wire into the wire-cutting reference hole.