To provide a photosensitive composition excellent sensitivity, plate wear, chemical resistance and preservation stability by containing two or more kinds of specific triazine compound a photopolymerization initiator.

This photosensitive composition contains an ethylenic unsaturated double bond-containing monomer, an alkaline water-soluble or expansive acidic vinyl copolymer and a photopolymerization initiator. The photopolymerization initiator contains two or more kinds of triazine compounds expressed by a formula, where R1 indicates a substituted or unsubstituted aliphatic group or aromatic group, R2 and R3 independently indicate the haloalkyl group. The alkaline water-soluble or expansive acid vinyl copolymer preferably has an unsaturated group in a side chain, and the unsaturated group of the side chain preferably is an allyl group and/or a vinyl group. A copolycondensation compound preferably contains a diazo resin, an aromatic compound acid radical having particularly a carboxyl group and/or a hydroxyl group, and an aromatic diazonium compound acid radical as constituting units.