PURPOSE: To stabilize an arc and to suppress the generation of spatters so as to improve welding workability by incorporating specific ratios of hydrogen and oxygen by the total weight of a wire for CO2 gas shielded arc welding into said wire.

CONSTITUTION: 0.0005W0.1000% hydrogen and 0.0040W0.0500% oxygen by the total weight of the wire base material are incorporated into the wire base material. A film is formed on the surface of the,wire base material by using a thermoplastic resin such as PE, PP or polystyrene and a prescribed ratio of the hydrogen is incorporated therein. The material is then subjected to a heating treatment in an oxidizing atmosphere of air, etc., to form oxide on the surface and to incorporate a prescribed ratio of the oxygen into the surface. Welding workability is improved by the wire constituted in the above-mentioned manner.