A printing press, and an apparatus and a process for regenerating a printing plate can repetitiously reuse the same printing plate and shorten time for decomposition of image areas formed by a hydrophobic organic compound under irradiation with activating light to delete the image areas. A process for regenerating a printing plate including a photosensitive layer, formed on the surface of a substrate, having a photocatalyst exhibits hydrophilicity responsive to activating light having energy higher than the photocatalyst's band-gap energy, and one or more hydrophobic image areas, formed on the surface of the photosensitive layer and operable to hold ink, comprises the steps of: removing ink remaining on the printing plate; hydrophilizing the surface of the printing plate by irradiating with the activating light and by heating the printing plate to delete the hydrophobic image areas; and applying an organic compound onto the printing plate.