An ingot slicing apparatus is provided to form a plurality of sheets of silicon substrates and to minimize slicing loss of an ingot by performing an ingot slicing process once. A plurality of wires(120) are formed to surround one side of a main roller(110). A plurality of pieces of diamond are attached to the plurality of wires to slice a cylindrical ingot. A plurality of reels(130) are disposed apart from the main roller to adjust tension of each of the wires. The wires are wound around the reels. A driving unit rotates the reels to move the wires in a longitudinal axis of the ingot. A diameter of the main roller is larger than a diameter of the ingot. The reels are arranged in a diagonal direction to adjust a gap between the wires.
