PURPOSE: To prevent oxidation at the conventional molten metal top pouring and enable obtaining of good-quality cast ingot by directly connecting rounders to the outlet and inlet respectively of the holding furnace body and disposing a vertically movable insert body which controls the molten metal holding amount within the above-mentioned furnace.

CONSTITUTION: A holding furnace 7 is so constituted that the molten metal in the holding furnace 7 may be supplied to the lower stream in a desired control state by connecting rounders 6 and 5 to the outlet and inlet of the molten metal furnace 7 provided between a melting furnace and casting machine, making the holding furnace body 7 stationary and disposing an insert body 8 which is vertically movably suspended by a prime mover 14 and screw jacks 13, 13' within the body 1. As a result of this, the conventional top pouring of molten metal is eliminated and the increase in the oxygen component amount in the molten metal occuring in the inclusion of the oxide produced in the falling portions of the molten metal is prevented, whereby the cast ingot of extremely good quality may be obtained.