An organic electroluminescence device includes a support substrate, a first transparent electrode on the support substrate, an organic light-emitting layer on the first transparent electrode, a second transparent electrode on the organic light-emitting layer, and a high refractive index layer arranged between the support substrate and the first transparent electrode, having at least one layer having a refractive index greater than or equal to a refractive index of the support substrate, having a light dispersion portion for dispersing incident light from the organic light-emitting layer, and having a planar surface contacting the first transparent electrode.