PURPOSE: To obtain a compsn. capable of developing with water and is useful for the photosensitive layer of the letterpress printing, intaglio printing, and lithographic press by composing the compsn. of completely or partially saponified polyvinyl acetate and photopolymerizable monomer having ethylenic unsatd. bond in the molecule, etc.

CONSTITUTION: The photosensitive resin compsn. of this invention is constituted of component A, B, C described hereunder. The component A: 100pts.wt. completely of partially saponified polyvinyl acetate having 50W100mol% degree of saponification. The component B: 20W200pts.wt. photopolymerizable monomer having ethylenic unsatd. bond in the molecule. The component C: 1W50pts.wt. polymer obtd. by homopolymerizing a polymerizable unsatd. monomer having residues expressed by the structural formulas ( I ) and (II) in the molecule or by compolymerizing the monomer with other unsatd. monomer. The average degree of polymn. of most preferred completely or partially saponified polyvinyl acetate for the component A is 500W3,000. ≥2 kinds of compd. having different degree of saponification or degree of polymn. for the component A may be used in combination.