To provide a photopolymerizable composition which cures under visible light or infrared laser with high sensitivity, is useful as a photosensitive layer of a negative original plate for a planographic printing plate capable of direct recording from digital data of a computer or the like and attains excellent aging stability, high-quality image formation and high printing and chemical resistances.

The photopolymerizable composition comprises (A) a polymerizable compound having at least one radical-polymerizable ethylenically unsaturated double bond per molecule and a cohesive energy density of ≥500 J/cm3, (B) a radical polymerization initiator and (C) and a binder polymer and cures when exposed to light. If the photopolymerizable composition further contains (D) a compound which generates heat upon exposure to IR, it cures when exposed to infrared laser.