PROBLEM TO BE SOLVED: To provide a treatment apparatus of a peracetic acid-containing effluent capable of effectively treating, even in a case where cations coexist, a peracetic acid-containing effluent and of decreasing the residual quantity of acetic acid within the treated water.SOLUTION: The provided treatment apparatus 1 of a peracetic acid-containing effluent includes a reducing column 12 for reducing peracetic acid within a peracetic acid-containing effluent, an anion exchange resin column 14 filled with a weakly basic anion exchange resin for treating the water having undergone the reducing treatment within the reducing column 12, and a mixed bed-style ion exchange resin column 16 filled with a strongly acidic cation exchange resin and a strongly basic anion exchange resin or weakly basic anion exchange resin for treating the water having undergone the anion exchanging treatment within the anion exchange resin column 14.
