A fiber-reinforced light alloy cast article for use in various mechanical parts such as, for example, a connecting rod, a rocker arm, and so forth in an internal combustion engine. The composite light alloy cast article includes therein a portion filled with a shaped body made of an inorganic fiber material of high elasticity and high mechanical strength, and another portion filled with a shaped body of inorganic fibers having low elasticity and high hardness and having an appropriate bulk density suited for required purposes, the fiber-shaped bodies being filled in the required portions of the composite light alloy cast article by high pressure solidification casting.