PURPOSE: To obtain an erasing liquid for planographic printing plate having an improved erasing property capable of only the desired image part without adversely affecting the proximate image parts without incorporating a host therein.

CONSTITUTION: The host is incorporated into the erasing liquid. After the photosensitive planographic printing plate is exposed with the image, the printing plate is processed with a processing liquid contg. the host and is then developed by a developer. Any compds. which are capable of clathrating water or org. molecules are adequate as the host to be used and are more preferably org. compds. which are soluble in a solvent to be used for preparing the erasing liquid. Such host is exemplified by, for example, annular D-glucans, cyclophanes, neutral polyligands, annular polyanions, cyclic polycations, cyclic peptides, spherands, cavitands and their acyclic analogous substances.