To provide: a fine-denier polyester yarn having excellent breakage preventing performance and lightness, in addition to excellent weather resistance and dimensional stability which are inherent in polyester fiber textile, and capable of being formed as a fabric suitable especially for sport gear using air pressure and requiring lightness such as a paraglider; and a method for manufacturing the same.

Provided is a fine-denier polyester fiber including ethylene terephthalate as a main repeating unit, the fine-denier polyester yarn satisfying all the following properties: (1) intrinsic viscosity (η)F(dl/g) of 0.70-1.00; (2) total fineness (dtex) of 8-20; (3) single filament fineness (dtex) of 1-4; (4) breaking strength (cN/dtex) of 5.3 or more; (5) breaking ductility (%) of 20 or more; (6) boiling water shrinkage (%) of 3-5; and (7) entanglement number (point/m) of 10-30.