The present application relates to a multielectrode gas-shielded 
arc welding method in which a filler wire is inserted between leading and trailing electrodes, a distance between the electrodes is 20 to 30 mm. Variables L, T, F, X, Y, alpha, beta, gamma and satisfy the following expressions: 40 DEG <= L<= 60 DEG, 40 DEG <= T <= 60 DEG, X + 5 DEG <= F <= X + 20 DEG or Y - 20 DEG <= F <= Y - 5 DEG, 4 DEG <= alpha <= 14 DEG, 5 DEG <= beta <= 15 DEG, - 5 DEG <= gamma <= 5 DEG, where X represents the larger one of a leading-
electrode horizontal angle L and a trailing-
electrode horizontal angle T, Y represents the smaller one of the angles, F represents a filler-wire 
torch angle, alpha represents a leading-
electrode backward angle, beta represents a trailing-electrode 
forward angle, gamma represents a filler-wire 
torch forward or backward angle. A target position of the filler wire is within a range between a lower end of the vertical plate and a position at a height of (upper 
leg length - 2 mm) from the lower end. According to the method, the shape of the 
welding bead can be remarkably improved, the arc 
noise between the leading and trailing electrodes can be reduced, and the equipment is easy.