Abstract: The apparatus provides for continuously manufacturing a flat twisted cable composed of a plurality of single-conductor pairs having alternate oppositely directed twisted portions with straight portions therebetween. The apparatus has a multi-stage single-conductor pair supply unit, a twisting unit, a reciprocatingly movable untwist preventing unit, a lateral spacing and converging unit, a reciprocating movable welding unit, and a take-up unit. The untwist preventing unit has piston operated pins for preventing the propagation of the twist from the preceding and following twisted portions of the flat twisted cable to the straight portions of the single-conductor pairs thereof. The welding unit has a reciprocatingly movable welder. The welding unit commences movement together with the straight portion when the latter reaches a position within the welder which performs the high frequency induction welding of the insulation coverings of straight portions to each other during movement.