The present invention provides an infrared photosensitive composition
including a binder polymer (A), a polymerizable compound (B), an infrared
absorber (C), and a compound (D) which can generate radicals by the
action of light or heat, wherein an acid value of a film produced from
the composition is from 0.15 mmol/g to 0.8 mmol/g. The invention also
provides a planographic printing plate precursor including a substrate
having disposed thereon a recording layer that contains the infrared
photosensitive composition.