Provided is a waste water treatment method that can simply and with high efficiency remove heavy metal from waste water containing heavy metal, and that comprises the following steps (i) and (ii). (i) An insolubilization step, in which an oxidizing agent and a coprecipitation agent are made to act on waste water, and the heavy metal in the waste water is insolubilized; and (ii) a separation step, in which the insolubilized heavy metal is removed from the waste water from step (i). Further provided is a waste water treatment device that has an oxidation tank, a coprecipitation tank, an insolubilization tank, and a separation device.
