A polyester resin that can be beneficially employed as one finding application in deactivation of polycondensation catalysts for polyester production and suppression of forming of acetaldehyde and other aldehydes and cyclic ester oligomers at molding stage. In particular, there is provided a polyester resin composed mainly of an aromatic dicarboxylic acid component and a glycol component wherein a phosphorus compound is incorporated through copolymerization or blending in an amount of 100 to 10,000 ppm in terms of phosphorus element, characterized in that the contents of Zn element, Fe element, Ni element and Cr element are not greater than specified values.