PURPOSE: An organic light emitting display device is provided to suppress a Newton's ring phenomenon while increasing visibility, thereby increasing the display quality of the organic light emitting display device. CONSTITUTION: An organic light emitting device(500) emits light onto a first substrate(100). A second substrate(200) faces the first substrate. The organic light emitting device is between the first and second substrates. Sealant bonds and seals the first and second substrates. A refractive index changing unit(600) comprises a moth eye layer(610) located on the second substrate. The refractive index changing unit includes an air layer(620) formed between the moth eye layer and the organic light emitting device.
