PURPOSE: To stabilize the feed at welding process by forming the wire feeding out through a push method to rather a helical or wave form, etc., in the circumferential direction.

CONSTITUTION: By rotating a toothed pully 7 through a toothed belt and motor, a welding wire is feeded out in the arrow mark direction with catching by feed out rollers 12, 13, a forming die 8, which is arranged with off centered to the toothed pully 7, makes eccentric motion, forming the welding wire into a hilical form. At this time, a pitch of the helicoid is decided by a feed out speed of the welding wire 15 and rotating speed of the toothed pully, the forming die 8 is tilted to naturally matched to a lead angle of the helicoid by a spherical bearing 9, forming the welding wire 15. The helical winding diameter is 5 times of the welding wire diameter and pitch is ≥2 times of winding diameter. By this wire forming, the insulation length is increased and toughness is improved, the feed resistance at spring liner in wire feed process is dispersed, absorbing and stabilizing the feed resistance difference generated by the attitude change of robot wrist.