To obtain a hypoeutectic Al-Si alloy casting with which in the case of desiring to secure locally high hardness on the surface and toughness in the inner part in an integral formed product, or to improve the toughness on the surface thereof a design of parts satisfying these required characteristic and lightening thereof can be performed and which can be produced at a low cost, and to obtain its producing method.

A pressurizing pin is insented in molten metal for the hypoeutectic Al-Si alloy casting in a product cavity to pressurize the molten metal when the molten metal is in a molten or semi-solidified state, and consequently part of the metallic structure is changed to an eutectic silicon agglomerated layer, a mixed layer of non-dendritic primary crystal and eutectic silicon and to mixed layer of dendritic primary crystal and eutectic silicon toward the inner part from the surface of the casting.