A photopolymerizable composition comprises: (i) a polymerizable compound carrying an addition-polymerizable unsaturated bond; (ii) a methine compound; (iii) at least one compound selected from the group consisting of: (a) compounds having carbon-halogen bonds, (b) aromatic onium salts, (c) organic peroxides, (d) thio compounds, (e) hexaaryl-biimidazoles, (f) ketooxime esters, and (g) compounds represented by the following general formula (III): ##STR1## wherein R.sup.6, R.sup.7, R.sup.8 and R.sup.9 may be the same or different and each represents a substituted or unsubstituted alkyl, aryl, alkenyl, alkynyl or heterocyclic group, provided that at least two of R.sup.6, R.sup.7, R.sup.8 and R.sup.9 may be bonded together to form a ring structure and that at least one of them represents an alkyl group; and Z.sup.+ represents an alkali metal cation or a quaternary ammonium cation. The composition has a high sensitivity to a wide range of actinic light rays extending from ultraviolet to visible light.