PURPOSE: To produce a polyester knit or woven fabric having acute-angled creases excellent in permanence properties and having an appearance similar to that of creases of a washed cotton fabric by weaving a fabric using a spun yarn of polyester fiber prepared by spinning at ≥a specified speed and carrying out softening process thereof using a jet dyeing machine.

CONSTITUTION: A spun yarn is formed using a polyester fiber spun at ≥6000m/min. A fabric woven using the above-mentioned spun yarn is charged into a jet dyeing machine and subjected to softening process. The weight of the above-mentioned fabric is preferably 100-250g/m2, especially preferably 150-220g/m2 and the condition of the softening process is preferably 30min. at 110°C-120°C. The temperature is preferably raised quickly from 60°C to 110-120°C at a rate of ≥5°C/min. and reduced quickly after the processing and discharge of the waste liquid is preferably carried out quickly at a high temperature of ≥100°C.