To provide a method for cleaning an alignment layer by which a foreign matter such as dust adhering to an alignment layer surface is effectively removed without lowering the aligning function of the alignment layer.

In a state of pressing an artificial chamois leather 31 fitted to a chamois leather fitting part 16 against a surface of a polyimide film 43 of a substance to be cleaned 41, the chamois leather fitting part 16 is made to rotate with respect to the arm part 15 while the substance to be cleaned 41 placed on a rotating support pedestal 12 is being rotated in a horizontal plane parallel to the surface of a base platform 11 and an arm part 15 of a scrub treatment device 13 is being made to revolve and oscillate within a specified angular range in the horizontal plane with a revolving drive part 14. At the same time, a cleaning liquid is supplied to the surface of the polyimide film 43 of the substance to be cleaned 41 from the tip of a nozzle part 19 by using a cleaning liquid supply device 17. Thereby the surface of the polyimide film 43 of the substance to be cleaned 41 is subjected to the scrub treatment extending over its full surface by using the artificial chamois leather 31 fitted to the chamois leather fitting part 16 of the scrub treatment device 13 and the surface of the polyimide film 43 is cleaned.