PURPOSE: A refining agent which consists in using CaO as its main component, and adding specific amounts of assistants comprising silicicaluminate and alkaline earth metal fluoride of the specific formulation and which is used for refining particularly by a ladle injection treating method.

CONSTITUTION: The refining agent comprises essentially CaO and is added with ≤20wt% the assistant comprising 25W75wt% silicic aluminate contg. oxide of alkali metals or silicic aluminate, and 75W25wt% fluoride of alkaline earth metals. In producing such refining agent, calcium carbonate, quicklime, slaked lime, etc. are used as the CaO source, potassium feldspar, sodium feldspar, etc. as the silicic aluminate contg. oxide of alkali metals, and fluorite is used as the fluoride of alkaline earth metals. These are then compounded to the above-mentioned composition which is then controlled to grain sizes of about ≤1mm, and is calcined in a rotary kiln.