To provide a method for producing an oxidized polysaccharide, by which an N-oxyl compound catalyst can be recovered and reused to produce the oxidized polysaccharide having excellent profitability and stable quality.

The method for producing the oxidized polysaccharide, comprises oxidizing the polysaccharide in an aqueous solvent containing the N-oxyl compound catalyst and an oxidizing agent. The method includes a process for recovering the N-oxyl compound catalyst by distillation from the reaction solution after the oxidation reaction of the polysaccharide.