PURPOSE: To prevent the elusion of alumina in a molten steel and to decrease inclusions by subjecting at least the part to be exposed to the molten steel of the inside wall of a vessel for refining lined with alumina refractories to coating with a zircon refractory layer to a specific thickness.

CONSTITUTION: At least the part to be exposed to the molten steel of the inside wall constituted of alumina and high alumina bricks is coated with the zircon refractory layer. The coating layer is formed by spray-coating the zircon refractories having 80W90μm grain size to 10W50mm thickness, then subjecting the coating to a heating treatment at a prescribed heat pattern. The in-steel inclusions are decreased by using the vessel constituted in the above-mentioned manner.