It is intended to provide an organic peracid polymer composition which is stable, odorless and has sufficient water solubility and is suitably used as a bactericide and a bleaching agent and a cleaning agent. By mixing and dissolving an organic acid polymer and hydrogen peroxide and an inorganic acid and maintaining the mixture for a period ranging from 1 hour to 1 month at a temperature ranging from 10 to 80 C., the organic peracid polymer-containing composition containing an organic peracid polymer (2 to 50% by weight) and, in some cases and the hydrogen peroxide (2 to 50% by weight) and the inorganic acid (0.1 to 10% by weight) is obtained.
