PURPOSE: To efficiently wash and remove the stains sticking to the surfaces of ferrite worked parts by electrolytic alkaline water of city water during the production stage of these parts.

CONSTITUTION: The electrolytic alkaline water of pH9 to 10.5 is stored in a washing tank 19a by electrolyzing the city water with an electrolysis device 1. A heater 20 is disposed within the washing tank 19a to heat the alkaline water to 40 to 60°C. The ferrite worked parts are washed by methods, such as immersing, stirring and showering, using this alkaline water. As a result, the ferrite worked parts are efficiently washed with excellent environmental maintenance.