An ink composition for ink jet printing is provided which gives a cured object excellent in adhesion to metallic plates, resistance to etchants, and alkali removability and can be stably ejected with an ink jet apparatus. The ink jet composition for etching resists has a viscosity at 25° C. of 3-50 mPa s and includes monomers comprising: either a polymerizable phosphoric ester compound represented by general formula (I); a polyfunctional monomer having two or more ethylenic double-bond groups per molecule and having no phosphoric ester group, the content of the ethylenic double-bond groups being 4×10−3 to 8×10−3 mol/g; and a monofunctional monomer having one ethylenic double-bond group per molecule and having neither phosphoric ester group nor carboxy group. In the formula, X represents C1-3 alkylene, Y represents C2-3 alkylene, and R represents hydrogen or methyl.