A resin composition contains poly(lactic acid) and a cellulosic ester, a resin composition excellent in transparency, mechanical properties, and thermostability; a biaxially drawn film containing poly(lactic acid) and at least one compound selected from cellulosic esters, poly(meth)acrylates, and polyvinyl compounds having a glass transition temperature of 60.degree. C. or higher; and a biaxially drawn film excellent in transparency, mechanical properties, and thermostability. The resin composition is obtained by melt-kneading a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and a cellulosic ester; a resin composition excellent in transparency and having luminous transmittance of 40% or higher for visible light with 400 nm; a molded article and a film made of the resin composition; a poly(lactic acid) biaxially drawn film containing a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and at least one compound selected from cellulosic esters, poly(meth)acrylates, and polyvinyl compounds having a glass transition temperature of 60.degree. C. or higher; a poly(lactic acid) biaxially drawn film excellent in transparency and having film haze of 10% or lower.