Method for producing a welded structure

Two steel plates which can prevent generation of a through-hole in the welded portion (53) and (51, 52) by laser welding (11), butt while supplying an assist gas (12) to the molten pool (13) surface a method of manufacturing a welded structure by welding, the thickness of the at least one steel plate of the two steel plates (51, 52) (52) is at 0.6mm or less, the assist gas (12) is 10 a mixed gas containing 50 vol% of