An electrolytic treatment apparatus for applying an electrochemical treatment by supplying an alternating current between a material being treated and a counter electrode in an electrolyte, wherein said electrolytic treatment being carried out by forming the counter electrode by a main counter electrode and an auxiliary counter electrode, connecting a circuit for the auxiliary counter electrode, in parallel, to a circuit connected to the main counter electrode, providing a diode or a mechanism of performing a diode-like action in the circuit for the auxiliary counter electrode for controlling an anode current in the main counter electrode, using an electrode containing magnetic iron oxide as the auxiliary counter electrode. The deterioration of the auxiliary counter electrode can be prevented without reducing the electrolytic treatment capacity, and cost for the equipment preservation can be greatly reduced.