PURPOSE: To reduce inclusion in molten metal flowing to a mold by making a diameter of flowing-through hole of the molten metal in a tundish weir to less than the specific value and forming an angle of this hole at the specific angle upward to the flowing-through direction of the molten metal.

CONSTITUTION: The tundish weir 1 having trapezoid shape and made of refractory, is set in the tundish 3 as turning the base upward. In this tundish weir 1, plural flowing-through holes 2 of the molten steel having less than 80 mm diameter in the surface are formed. Further, the flowing-through hole 2 of the molten steel is formed as inclining to vertical direction, for example, at 5° angle to the surface and the weir 1 is set, so as to make the hole 2 upward to the flowing-through direction of the molten steel. The molten steel supplied into the tundish 3 from a ladle is passed through the flowing-through holes 2 in the weir 1, 1 to flow toward discharging holes 6, 6 of the molten steel. This molten steel flow speed is largely decreased, because the diameter of holes 2 is small, and the ascending flow is flowed by inclination of holes 2 as the above-mentioned, and so floating effect of inclusion is obtd.