PURPOSE: To enable casting of a this sheet having good surface characteristic with high quality and high yield by using a graphite-made mold and executing casting in the condition of reducing the pressure, at the time of manufacturing the metal thin sheet by casting method.

CONSTITUTION: At the time of casting the metal thin sheet, by using the graphite-made mold 2, the casting is executed in the condition of reduced pressure at the casting temp. of ≥1000°C. As the graphite-made mold has large thermal conductivity, the surface characteristic is improved. Burning phenomenon is avoided and crack is not developed. As the graphite has small coefficient of thermal expension, the mold deformation caused by the heat is small and the deformation of cast block is restrained to be small and the dimensional precision is improved. Because of the casting in the reduced pressure, the generation of blow holes is reduced, and as the mold deformation is small, the thickness difference of the sheet is difficult to develop and micro porocity is reduced. By this method, a target material for forming the thin sheet without various defects of crack, etc., can be manufactured at a low cost and with high quality.