To provide a waste water coagulation technology capable of easily setting appropriate reaction conditions in using an actual apparatus, and effectively removing turbidity.

The organic coagulant coagulates suspended matter in waste water, and includes at least a DMAPAA (quarternized methyl halide of dimethylaminopropyl acrylamide)-based organic coagulant component, and a cationic polymer coagulant component. The DMAPAA-based organic coagulant component and cationic polymer coagulant component may be present as independent polymers, or in a copolymerized state. The waste water coagulation method uses the organic coagulant.