PURPOSE: To improve the feeding of a wire and the workability in welding by forming a thermoplastic resin film on the surface of a metal wire rod and coating an oily lubricant in the amt. at a specific rate for the weight of a wire on the surface of the film.

CONSTITUTION: A welding wire 16 is formed by coating the film in an electrifiable thickness with the thermoplastic resin 12 of a polyethylene resin, etc., on the metal wire rod 10 for wire. The wire 16 is fed to perform a welding by coating an oil lubricant 14 at the rate of 0.1g min. 10g max. per 10kg wire on the surface of the resin film 12. Owing to the oily lubricant in an optimum amt. being coated besides forming the thermoplastic resin 12 on the surface of the metal wire rod 10 the residue of the resin film 12, the wear of the wire feeding port inside a feeding chip, etc., are prevented, the feeding of the wire is improved and the generation a feeding stoppage and line stop are prevented. Consequently the workability in welding is improved as well as the feeding of the wire.