The ink comprises a coloring component, a reactive oligomer and/or a reactive prepolymer, a reactive diluent and a photoinitiator, wherein the reactive oligomer and/or reactive prepolymer unit and the reactive diluent unit have a glass transition point of 0 to 70 C., respectively, in a polymer obtained therefrom. In the present invention, a cured film excellent in adhesion to materials and scratch resistance is obtained, and an image without blurring is formed in ink jet printing of the ultraviolet ray curable ink. An ultraviolet ray curable ink composition having a viscosity of 60 to 800 cps at 25 C. which comprises a coloring component, a reactive diluent, a photoinitiator and an oligomer and/or reactive prepolymer having compatibility with the reactive diluent is used. The ink composition is heated to 40 to 150 C. and applied to a recording medium and cured by ultraviolet rays.