PURPOSE: To make effective use of a photomask blank by providing a stage for stripping the resist coated on the light shieldable film of the photomask blank by a resist stripping liquid, stage for removing the resist stripping liquid and stage for freshly coating the resist on the light shieldable film.

CONSTITUTION: The photomask blank with the resist is immersed in the resist stripping liquid in a resist stripping device to strip the resist while ultrasonic waves are propagated therein for 3min. The photomask blank is then successively immersed into the cleaning liquids which consists of an isopropyl alcohol and the housed in 3 pieces of cleaning tank. The photomask blank is subjected to 1min of ultrasonic cleaning respectively in said tanks, by which the resist stripping liquid is removed from the light shieldable film and the photomask blank is dried. The resist stripping liquid and cleaning liquid are thus thoroughly removed. The resist is freshly coated by a known spin coating method on the light shieldable film of such clean photomask blank. The film thickness is inspected, and if the film thickness is of a desired value, the photomask blank is subjected to stages for exposing, developing, etching of the light shieldable film, etc., which are post stages, by which the photomask is manufactured.