Provided is a manufacturing method of a bending module that forms a plurality of joint members by press-processing sheet material, with each joint member having a joint member body, a connection protrusion and a wire guide protrusion having a wire guide hole formed at one side corner of the joint member body, and one connection protrusion is formed at another side corner of the joint member body. The wire guide protrusions are folded with respect to the joint member bodies; a joint member assembly is formed by arranging the plurality of joint members in parallel and connecting neighboring connection members to connect the joint members together; the joint member assembly are bent to a ring shape; and each joint member is connect to each other by welding corners thereof.