Abstract: An apparatus for casting an ingot includes a molten metal reservoir (51) positioned at an upper portion, a casting chamber (5) positioned at a lower portion and a partition wall (3) between the reservoir and the chamber, a spruce (7) formed in the partition wall, an opening/closing plug (8) for opening and closing the sprue and control means for controlling an opening and closing operation of the plug. The casing chamber is defined in a mold (1) that includes a lower mold member (4), a side mold member (2) and the partition wall (3) that constitutes an upper mold member. At least one of the lower mold member, side mold member and upper mold member includes a plurality of divided sections (21,22) in accordance with a shape of a cast ingot C.