Disclosed are a processing liquid and a processing method that can favorably perform plate inspection of an on-press development-type lithographic printing plate precursor and image quality control, by using a processing liquid of a lithographic printing plate precursor having an image recording layer formable of an image by removing an unexposed region with at least one of printing ink and dampening water, the processing liquid containing a basic coloring dye expressed by General Formula (I) below and an anionic surfactant having an aromatic ring: wherein each of R1 to R14 independently represents a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, R10 and R14 may be bonded to each other to form a single bond, Ar1 represents a phenylene group or a naphthylene group, Ar2 represents an aryl group, and X− represents SO3− or COO−.