NOVELTY - A polyester composition comprises dicarboxylic acid having terephthalic acid as a main component, and diol component having ethylene glycol as a main component. The polyester composition has intrinsic viscosity of 0.65-0.90, carboxyl end group of 15 equivalent weight/t or less, and methoxy end group of 10 equivalent weight/t or less. The ratio of number of moles of alkali metal element or alkaline earth metal element per polyester (106) and number of moles of elemental phosphorus per polyester (106) in the polyester composition is 0.7-1.3.    USE - Polyester composition is used for film for solar cell. Uses include but are not limited to magnetic recording media, thermal stencil, reflecting plate, optical material, electric insulator, capacitor, mold release agent, ribbon and food packaging material.    ADVANTAGE - The solar cell formed using polyester composition is economical, and has excellent hydrolysis resistance and heat resistance.    DETAILED DESCRIPTION - A polyester composition comprises dicarboxylic acid having terephthalic acid as a main component, and diol component having ethylene glycol as a main component. The polyester composition has intrinsic viscosity of 0.65-0.90, carboxyl end group of 15 equivalent weight/t or less, and methoxy end group of 10 equivalent weight/t or less. The ratio of number of moles of alkali metal element or alkaline earth metal element per polyester (106) and number of moles of elemental phosphorus per polyester (106) in the polyester composition is 0.7-1.3. The number of moles of elemental phosphorus/106 g of polyester is 200-600 ppm. An INDEPENDENT CLAIM is included for manufacture of polyester composition, which involves performing esterification of ethylene glycol and dicarboxylic acid, adding alkali metal element and/or alkaline-earth metal element, phosphorus compound and polycondensation catalyst to the resultant reaction mixture, carrying out polycondensation reaction at 285 degrees C or less, and then performing solid-state polymerization reaction.