A light-curable inkjet printing ink composition characterized by good curability under ultraviolet light, particularly ultraviolet light from a light-emitting diode (LED) light source, good adhesion to a polyvinyl chloride sheet, etc., and good flexibility of the coating film of ink. As a means for achieving the object, a light-curable inkjet printing ink composition is provided that contains a light-polymerizable component and a light-polymerization initiator, where the light-curable inkjet printing ink composition contains 70 to 100 percent by mass of monofunctional monomers relative to the total mass of the light-polymerizable component; wherein the monofunctional monomers comprise: (A) a monofunctional monomer whose homopolymer has a glass transition temperature of 20°C or above; and (B) a monofunctional monomer whose homopolymer has a glass transition temperature of below 20°C; and (A) is contained by 30 to 90 percent by mass, while (B) is contained by 10 to 70 percent by mass, relative to the total mass of the light-polymerizable component.