An on-press planographic printing plate precursor, comprising: (i) a support; (ii) an image recording layer which (a) shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, and (b) comprises - a radical initiator which comprises an electron-donating radical initiator and an electron-accepting radical initiator, - a radical polymerizable component, and - a radiation absorption compound which is decomposable to generate a radical due to the image forming radiation and comprises a compound of formula: wherein R N is a hydrocarbon group, X 1 is O or S, X 2 is O or S, R 21 each independently is H, alkyl or aryl, and R 22 is aryl, alkoxy or an onium group; R 2 and R 3 each independently are H or optionally substituted alkyl, and R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 2 each independently are a group forming a benzene or naphthalene ring, Y 1 and Y 2 each independently are -O-, -S-, dialkylmethylene or -NR 0 - wherein R 0 is H, optionally substituted alkyl or optionally substituted aryl, R 4 and R 5 each independently are optionally substituted alkyl, R 6 -R 9 each independently are H or optionally substituted alkyl, and Za is a counter ion that neutralizes the charge; and (iii) a protective layer on the image recording layer. (i) a support; (ii) an image recording layer which (a) shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, and (b) comprises - a radical initiator which comprises an electron-donating radical initiator and an electron-accepting radical initiator, - a radical polymerizable component, and - a radiation absorption compound which is decomposable to generate a radical due to the image forming radiation and comprises a compound of formula: wherein R N is a hydrocarbon group, X 1 is O or S, X 2 is O or S, R 21 each independently is H, alkyl or aryl, and R 22 is aryl, alkoxy or an onium group; R 2 and R 3 each independently are H or optionally substituted alkyl, and R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 2 each independently are a group forming a benzene or naphthalene ring, Y 1 and Y 2 each independently are -O-, -S-, dialkylmethylene or -NR 0 - wherein R 0 is H, optionally substituted alkyl or optionally substituted aryl, R 4 and R 5 each independently are optionally substituted alkyl, R 6 -R 9 each independently are H or optionally substituted alkyl, and Za is a counter ion that neutralizes the charge; and (a) shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, and (b) comprises - a radical initiator which comprises an electron-donating radical initiator and an electron-accepting radical initiator, - a radical polymerizable component, and - a radiation absorption compound which is decomposable to generate a radical due to the image forming radiation and comprises a compound of formula: wherein R N is a hydrocarbon group, X 1 is O or S, X 2 is O or S, R 21 each independently is H, alkyl or aryl, and R 22 is aryl, alkoxy or an onium group; R 2 and R 3 each independently are H or optionally substituted alkyl, and R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 2 each independently are a group forming a benzene or naphthalene ring, Y 1 and Y 2 each independently are -O-, -S-, dialkylmethylene or -NR 0 - wherein R 0 is H, optionally substituted alkyl or optionally substituted aryl, R 4 and R 5 each independently are optionally substituted alkyl, R 6 -R 9 each independently are H or optionally substituted alkyl, and Za is a counter ion that neutralizes the charge; and - a radical initiator which comprises an electron-donating radical initiator and an electron-accepting radical initiator, - a radical polymerizable component, and - a radiation absorption compound which is decomposable to generate a radical due to the image forming radiation and comprises a compound of formula: wherein R N is a hydrocarbon group, X 1 is O or S, X 2 is O or S, R 21 each independently is H, alkyl or aryl, and R 22 is aryl, alkoxy or an onium group; R 2 and R 3 each independently are H or optionally substituted alkyl, and R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 2 each independently are a group forming a benzene or naphthalene ring, Y 1 and Y 2 each independently are -O-, -S-, dialkylmethylene or -NR 0 - wherein R 0 is H, optionally substituted alkyl or optionally substituted aryl, R 4 and R 5 each independently are optionally substituted alkyl, R 6 -R 9 each independently are H or optionally substituted alkyl, and Za is a counter ion that neutralizes the charge; and R N is a hydrocarbon group, X 1 is O or S, X 2 is O or S, R 21 each independently is H, alkyl or aryl, and R 22 is aryl, alkoxy or an onium group; R 2 and R 3 each independently are H or optionally substituted alkyl, and R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 2 each independently are a group forming a benzene or naphthalene ring, Y 1 and Y 2 each independently are -O-, -S-, dialkylmethylene or -NR 0 - wherein R 0 is H, optionally substituted alkyl or optionally substituted aryl, R 4 and R 5 each independently are optionally substituted alkyl, R 6 -R 9 each independently are H or optionally substituted alkyl, and Za is a counter ion that neutralizes the charge; and (iii) a protective layer on the image recording layer.