Provided are a resin composition containing poly(3-hydroxyalkanoate), the resin composition enabling a film or a sheet to be stably produced under practical processing conditions by inflation molding; and a method for producing the resin composition. The resin composition includes 100 parts by weight of poly(3-hydroxyalkanoate) and 5 to 15 parts by weight of an ester compound, and having a ratio of 3.5×10−2 to 4.8×10−2 (sec/[Pa·s]) between a melt viscosity (Pa·s) and a drawdown time (sec).