To provide various vitreous-layer-coated aluminum-alloy cast products in which vitreous layer coating is made possible by a new aluminum-alloy casting method or regulation of an aluminum-alloy composition.

An inorganic mold-coating material is applied to a metal-mold cavity and dried. Then a molten aluminum alloy is poured into the cavity to form a cast product. A coating solution prepared by forming vitreous particles into dispersion slurry using a disperse medium is applied to the cast product and then fired by heating. By this method, the vitreous-layer-coated aluminum- alloy cast product can be obtained.