A presensitized plate comprising a support for a lithographic printing
plate including an anodized layer formed on an aluminum plate and a
recording layer recordable by infrared laser exposure on the support,
wherein in a section of the anodized layer after the recording layer is
provided, an atomicity ratio of carbon to aluminum (C/Al) represented by
Auger Electron Spectroscopic analysis is 1.0 or less. In the case of
being used as an on-machine development type, it exhibits a good
on-machine development characteristic, a high sensitivity, a high press
life, and high scum resistance during printing and while left (ink
discharging). In the case of being used as a conventional thermal
positive or negative working type, it exhibits an efficient use of heat
for image formation, a high sensitivity, a high press life, and a slight
possibility of scum occurrence at non-image areas.