A welding method, which performs non-keyhole welding of a ferritic stainless steel having a plate thickness of 3 mm or less using a plasma welding torch (10), includes supplying an inert gas, as a pilot gas (23), into the gap between a tungsten electrode (11) and an insert chip (12) at a flow rate of 2.1 m/sec or less, and supplying a shield gas (24) into the gap between the insert chip (12) and a shield cap (15), wherein a mixed gas prepared by adding either 0.5 to 4 vol % of oxygen gas or 1 to 6 vol % of carbon dioxide gas to an inert gas is used as the shield gas (24).