PURPOSE: To execute both processes of the roughing and the cleaning of a surface at the same time, to uniformize the degree of surface roughness and to eliminate a remaining substance by processing the surface of an electrical conductive substrate to be the rough surface by a ultrasonic wave in solvent for cleaning.

CONSTITUTION: The cylindrical electrical conductive substrate 10 is immersed in the solvent for cleaning 3 in an ultrasonic consolidation system tank 2 while it is rotated. Then, the surface of the substrate 10 is processed by irradiating it with the ultrasonic wave from an ultrasonic wave generating element 4. At this time, the ultrasonic wave within the range of 28 - 200 kHz can be used. Thus, the random rough surface of a rugged state which is not oriented is formed. Besides, the group of halogenated hydrocorbon such as 1, 1, 1- trichloroethane can be used for the solvent 3.