To provide a method for producing an optical polyester resin excellent in heat resistance and wavelength dispersibility suitable for use in an optical base material such as a retardation film which is suppressed in the mount of an excess distillate during polycondensation and excels in production stability and quality stability.

The method for producing an optical polyester having a fluorene skeleton and not less than 80 mol% component having a monomer unit molecular weight of not less than 82 in the charge composition comprises allowing a distillate weight X excluding excess component for substantial transesterification on polymerization to meet specific conditions for the charge amounts.