To improve the production yield of a liquid crystal display device by spraying an atomized surfactant (detergent) on the surface of an electrode substrate when the electrode substrate is cleaned after-orientation treatment, and then cleaning the substrate with shower of a detergent.

The electrode substrate 14 consists of a glass substrate and a patterned transparent electrode, insulating layer and polyimide orienting film after orientation treatment deposited on the glass substrate, and the substrate 14 is successively carried by a beam carrying device through rooms 20 to 23 in a cleaning device 16. In a neutral room 20, a detergent 17 in an atomized state is sprayed from the position about 50cm above onto the electrode substrate 14 on the beam carrying device in such a manner that the detergent does not flow. Then the electrode substrate 14 covered with the atomized detergent 17 is cleaned with shower of the detergent 17 in a detergent shower room 22. Then in a pure water shower room 23, the electrode substrate 14 is cleaned with shower of pure water and then dried to complete the cleaning process. Thus, such a problem can be prevented that the detergent drops as large drops on the surface of the electrode substrate 14 and contaminants deposit around the drops.