A light emission device and a display device using the light emission device as a light source are provided. The light emission device includes first and second substrates facing each other and forming a vacuum vessel, an electron emission unit located on the first substrate, and a light emission unit located on the second substrate. The light emission unit includes a plurality of phosphor layers located on the second substrate and spaced from each other, a heat dissipation layer located between the phosphor layers and having an end extending to outside of the vacuum vessel to be exposed to air, and an anode electrode located at one side of the phosphor layers and the heat dissipation layer.