PURPOSE: To prevent flowing-out of slag at the time of pouring molten metal by dividing a triangular ladle into two parts of a molten metal receiving part and a molten metal pouring part with vertical partition wall and arranging a submerged weir at the lowest part in the vertical partition wall, a heat insulating cover on the upper face of the molten metal pouring part and a gas burner at the tapping hole.

CONSTITUTION: At the time of supplying the molten metal 19 into the molten metal receiving part 10 in the triangular ladle 6, the molten metal 19 is supplied into the molten metal pouring part 11 from the submerged weir 13 at the lowest part in the vertical partition wall 9. Then, the slag 20 on the molten metal surface in the molten metal receiving part 10 is cut off with the vertical partition wall 9 and not invaded in the molten metal pouring part 11. On the other hand, by blowing reducing flame 18 generated with the gas burner 17 to gap between the molten metal surface of the molten metal pouring part 11 and the heat insulating cover 16, as the molten metal surface in the molten metal pouring part 11 is brought into contact with the reducing atmosphere, the slag 20 is not generated. Successively, at the time of pouring the molten metal 19 in the molten metal pouring part 11 from the tapping hole 14 by tilting the ladle 6, even if a little quantity of slag 20 is generated, as the slag is blown off toward rear part at the tapping hole 14 with the reducing flame 18, it is not fear to flow out the slag 20.