PURPOSE: To obtain an ingot having little gaping defects by arranging the spe cific quantity of core metal at the specific position in a mold, melting it by heat of molten steel and solidifying it together with the molten steel.

CONSTITUTION: The core metal 6 is hung down at center part of hanger 5, and the hanger 5 is laid between center parts of upper ends for wall parts facing in a mold 2 and 500W1,000g of the core metal 6 per 1ton of ingot weight produced is hung down at the middle part of ingot and at the position of 30W60% from the upper end in the mold 2. Next, at the time of pouring the molten steel in each mold 2 through a molten steel pouring tube 3 and runner 4, the core metal 6 is melted by heat of the molten steel and solidified as time passed and so the ingot having little gaping defects is obtd.