A polylactic acid formed article and a production process therefor. A resin composition for the formed article comprises polylactic acid having an optical purity of not lower than 90% and a residual lactide amount of 0.1 to 0.6% by mass, and 1 to 25% by mass of a crystal nucleus agent. The formed article is characterized in that a difference (|ΔHm|−|ΔHc|) between the absolute value of a crystal fusion heat amount ΔHm as measured at a heat-up rate of 20° C./min by means of a differential scanning calorimeter and the absolute value of a heat-up crystallization heat amount ΔHc generated by heat-up crystallization is not lower than 25 J/g, and has a crystallinity of not lower than 35% as determined by X-ray measurement and a crystallization speed of not lower than 0.05 min−1 at 130° C.