A lighting apparatus using an organic light-emitting diode (OLED) of the present disclosure is characterized in that an inner light extraction layer is provided between a substrate and an OLED, and concurrently, a multi-buffer layer, of which a refractive index is gradually changed, is formed on the inner light extraction layer. According to the present disclosure, light extraction due to scattering may be improved by applying the inner light extraction layer, and a waveguide mode may be extracted as light by applying the multi-buffer layer, thereby improving luminous efficiency.