Provided is an ink set having excellent curing properties under LED light, providing printed matter that does not fade or discolor due to a photopolymerization initiator, suppressing color bleeding during image forming, exhibiting favorable adhesion towards a polyvinyl chloride sheet, enabling cock ring to be efficiently suppressed, and demonstrating an extremely low viscosity, high flash point and low skin irritation. The present invention pertains to an ink set containing at least two compositions selected from the group consisting of a yellow ink composition, a magenta ink composition, a cyan ink composition, a black ink composition, a white ink composition, and a clear ink composition, the compositions having the predetermined structure as specified in claim 1, wherein the flash point of the ink compositions is 70° C. or higher, and the viscosity (25° C.) is 5 mPa-s or lower.