PURPOSE: To allow the qualities of various waste photographic developer to conform to the water standard to the river.

CONSTITUTION: The waste photographic developer to be purified is electrolyzed to decompose all the components of the waste developer and to make it non- pollutional. As an auxiliary means for the electrolysis, the pH is regulated before, after or during the electrolysis and flocculation is conducted one to several times to enhance the treating effect, hence the treating time is shortened, and energy is saved. The device consists basically of an electrolytic cell 1 with an electrode 2 furnished on its bottom and is provided, as required, with chemical feeders 6, 7 and 8 or a flocculation tank (also used as the electrolytic cell) and an automatic controller 10.