To provide a test casting for an aluminum alloy casting having mechanical property similar to a metallic mold casting and particularly excellent toughness in nearly the same delivery time as by an ordinary sand mold casting, used for car parts of aluminum wheel, suspension device parts, etc.

In the producing method of this aluminum alloy casting in the sand mold, a position having high heat conductivity formed with the granular metals in a part or all of at least mold cavity, is arranged. After casting a member by pouring the molten metal into this mold and solidifying, the cast member is passed in such sufficient pressure that defect existing in the casting is compressed at the pressing temp. and thereafter, a T6 treatment is applied. The aluminum alloy casting having a composition contg., by wt.% 4-10% Si, 0.2-0.7% Mg, <0.2% Fe, 0-<6% Cu is used. A value of the strength index [3 ×tensile strength (MPa) + 40 × elongation (%)] in the mechanical property of the aluminum alloy casting solidified by contacting with the high heat conductivity position in the sand mold, is ≥1000. After casting, a treatment for plastic work is applied to a part or all of the casting surface.