To provide a method for extremely reducing the amount of used bleaching chemicals required for bleaching a pulp to a prescribed whiteness, and a method for easily purifying and obtaining a xylooligosaccharide eluted in a xylanase treating step in the method for producing a bleached pulp by treating the unbleached pulp by the xylanase treating step, and further treating the treated pulp by a multistep bleaching step.

This method for producing the bleached pulp by treating the unbleached pulp obtained by cooking a lignocellulose material by the xylanase treating step, and further treating the treated pulp by the multistep bleaching step comprises an acid-treating step formed just after the xylanase treating step.