Polyester fiber structures having good color tones (low b* values) and being excellent in moldability can be made from polyester fiber produced in the presence of a catalyst which comprises (I) a mixture consisting of a Ti compound component composed of one or more members selected from among titanium alkoxides of the general formula (I) and products of reaction of these alkoxides with carboxylic acids of the general formula (II) or anhydrides thereof and a P compound component consisting of a compound of the general formula (III) and/or (2) a product obtained by reacting a Ti compound component composed of one or more members selected from among titanium alkoxides of the general formula (IV) and products of reaction of these alkoxides with carboxylic acids of the general formula (II) or anhydrides thereof with a P compound component consisting of a compound of the general formula (V).