The present invention provides a planographic printing plate precursor including a support and a positive recording layer formed on the support and containing: (A) a polymer having a structural unit represented by the following general formula (1), (B) a photo-thermal converting agent, and (C) an amino compound having a methylol group or an alkoxymethyl group; and a positive recording layer whose solubility in an alkaline developer is improved by exposure to light or by heating.