An on-press development or non-
processing (non-development) type lithographic printing plate precursor capable of giving a printout image having a large
lightness difference, and a lithographic printing method using this lithographic printing plate precursor are provided, a lithographic printing plate precursor comprising a support and a photosensitive-thermosensitive layer capable of recording an image by
infrared laser exposure, the lithographic printing plate precursor being capable of performing a printing by loading on a
printing press without passing through a development
processing step after recording an image, or by recording an image after loading on a
printing press, wherein said photosensitive-thermosensitive layer comprises (1) an
infrared absorbent and (2) a discoloring agent or discoloration
system capable of generating a color change upon
exposure; and the lithographic printing method performing a printing using the above-described lithographic printing plate precursor.