To provide a light weight and high strength member, such as a handling part in an automobile having desirable mechanical characteristic.

In a producing method of the light weight and high strength member, such as chassis part of the automobile, molten aluminum alloy containing 4.0-10.5 wt.% Si and 0.3-1.3 wt.% Cu is pressurize-poured into a mold to cast a preform, and this preform is formed into a finish formed product with a hot-forging by using a forging die.