The present invention provides an application material capable of forming a thin layer of high quality having controlled refractive index, a coating layer formed by using said application material, an antireflection coating using said coating layer, an antireflection film and image display to which said antireflection coating is applied. A coating layer formed from a coating composition comprising (1) rutile type titanium oxide coated with an inorganic compound decreasing or eliminating a photocatalyst activity and an organic compound and/or organometal compound having an anionic polar group, and having a primary particle size in the range from 0.01 to 0.1 m, (2) a binder component having an ionizing radiation-curing property, (3) a dispersing agent having an anionic polar group, and (4) an organic solvent is suitable for forming a light transmission layer constituting a single-layer type or multi-layer type antireflection coating 17, partucularly, a middle refractive index layer 18, high refracive index layer 19 or hard coat layer 16 having high refractive index (FIG. 2).