The purpose of the present invention is, in gas shielded arc welding using an active gas and flux-cored wire with primer-coated steel plates as a base material, to suppress occurrences of poor appearance in welded parts caused by pores originating in the primer. A welding method for a welded article positions a first steel plate and a second steel plate formed from primer-coated steel plates in a T shape and welds each of corner parts formed in two locations. Using flux-cored wire (100), which is formed by filling the inside of a steel outside skin with flux, and a shielding gas (carbon dioxide gas), a welding pool (400) is formed in the corner part by supplying a welding current to the corner part via an arc from the flux-cored wire (100) by means of the shielding gas; additionally, an alternating magnetic field is applied to the welding pool, and the welding current and the alternating magnetic field are set such that the welding current (A) and the magnetic flux density (mT) for the alternating magnetic field have a relationship of 20000 ‰¤ welding current × magnetic flux density ‰¤ 30000.