The invention provides a planographic printing plate precursor, utilizing a support
member having a hydrophilic surface excellent in hydrophilicity and durability,
providing effects of improving scumming in the printing operation and capable of
forming large numbers of prints of high image quality even under severe printing
conditions. The precursor comprises a support including an aluminum substrate and
a hydrophilic layer disposed thereon, the hydrophilic layer formed by chemically
bonding a hydrophilic polymer, which includes a reactive group able to chemically
bond to a surface of the aluminum substrate directly or via a structural component
comprising a crosslinked structure; and a positive working recording layer disposed
on the support and including a light-absorbing and heat-generating material, and
a polymer compound, which is insoluble in water and soluble in alkali, wherein
solubility of the recording layer in an alkaline aqueous solution increases upon
exposure to light.