To economically execute the welding into high strength without developing crack in a short time by interposing a slender steel barrier plate into a gap of a rail to be welded, generating the arc between an electrode and the barrier plate and burying the gap above the barrier plate with a filler welding metal in a gas shield electric arc welding method.

Rails 10, 12 are placed on a lower part block 150 in the interval having gap (g). Into the gap (g), the barrier plate P having larger width than the gap width, is inserted. Below the barrier plate P, a ceramic-made insulating material 154 is desirable to arrange so as to overlap to the bottom parts of the rails 10, 12. The barrier plate P is a low carbon-containing steel and has 0.05-0.3 inch thickness and the end surfaces 210, 212 are made to chamferring. When an electrode 260 in arc welding gun 250 is advanced downward, the arc C is generated between the barrier plate P and the electrode 260. The welding method is used for a multi-pass arc welding method.