A nonwoven fabric of polyester composite fibers which has a satisfactory color tone (low value of b*). It is formed from short composite fibers obtained from a polyester polymer obtained with the following catalyst and a fusion-bondable polymer. The catalyst comprises: (1) a mixture of a phosphorus compound ingredient comprising a phosphorus compound represented by the formula (III) with a titanium compound ingredient comprising a titanium alkoxide represented by the following formula (I) and/or a product of the reaction of the titanium alkoxide with a carboxylic acid represented by the formula (II) or anhydride thereof; and/or (2) a product of the reaction of a phosphorus compound ingredient comprising a phosphorus compound represented by the formula (V) with a titanium compound ingredient comprising a titanium alkoxide (IV) represented by the formula (IV) and/or a product of the reaction of the titanium alkoxide with a carboxylic acid represented by the formula (III) or anhydride thereof.