PURPOSE: To improve the structure of a casting ingot in bottom pouring ingot making having a heat insulating or exothermic riser part by disposing an exothermic riser holding plate having a specific angular projecting shape at the center on a covering material for the molten metal surface and heating the molten metal surface from the central part without ignition delay and variance.

CONSTITUTION: A riser holding plate 7 which is formed at the center into a projecting shape having 3W50°, more preferably 3W30° average angle of inclination and of which at least the bottom surface is formed of an exothermic material is disposed on a covering material 5 on the surface of a molten metal 6 in a bottom pouring casting mold 1 having a heat insulating or exothermic sleeve 4 in a riser part 2. The plate 7 expels the material 5 by the central projecting part and is ignited to generate heat from around the central part of the molten metal, thereby heating the central part of the molten metal. The solidifying rate in the central longitudinal direction of the casting ingot is adjusted and the central structure is improved.