PURPOSE:To shorten the length of a connection part to the irreducible minimum, and make the connection part and an opening part in a desired shape, forming the connection part intermittently, by integrally forming continuously a supporting wire, a cable main body, and the connecting part, and then forming an opening part. CONSTITUTION:A high-tensile strength wire 1 such as a steel wire and a cable lore 2 are led to the cross head 12 of an extruder 11 of thermoplastic resin in a parallelly arranged condition from a supply drum. Next, synthetic resin in a melted condition is batch-coated 3 on the wire 1 and the core 2 to integrally form a supporting wire 4, a cable main body 5, and a connection part 6 in the head 12, and then a resultant is cooled and solidified in a cooling tank 13. The part 6 is partially punched, that is, punched in a desired dimension by a punching machine 14 forming an opening part 7, and a self-supporting cable is obtained, which is in a desired cross section shape having the part 7 and in a 8-shaped cross section having the part 6 remained intermittently at length sufficiently short as required. Consequently, the dimension of the part 6 can be formed in the smallest dimension, in which connection strength is sufficient as required for bearing dead weight and wind pressure, and also the shape and dimension of the parts 6 and 7 can be made high accurately.