PURPOSE: To remove waste of molten metal raw material by introducing gas for base metal and gas for combining the base metal to the gas atomizer at the same time and dispersing the metal compound to the base metal.

CONSTITUTION: The gas atomizer 2a is arranged around outer circumference of lower nozzle 2 in a tundish 1 and single system gas pipe 11a and mixing system 12 gas pipe 12a are connected. by arranging a changeover valve 3 in a gas pipe, branch pipe 15 from single system 11 gas supplying source 11b and additional system 13 gas supplying source 13b are communicated. Molten metal is slenderly flowed down from a nozzle 2 in a tundish 1, and the changeover valve 3 is controlled, and only by blowing the mixed gas of the single system 11 and the mixing system 12 through the atomizer 2a, the solidified-state semi-forming metal compound, dispersing the compound, is obtd. Therefore, the waste of the molten metal raw material in the tundish 1 is removed.