A backlight device includes a first substrate having optical transparency and having a first surface and a second surface. An LED thin-film is fixed to the first surface of the first substrate. The LED thin-film is formed of epitaxially grown inorganic material layers as a P-N junction device. An anode electrode and a cathode electrode are formed on the LED thin-film. An anode driver IC and a cathode driver IC are provided for driving the LED thin-film. An anode wiring is provided for connecting the anode driver IC and the anode electrode, and a cathode wiring is provided for connecting the cathode driver IC and the cathode electrode. A second substrate has optical transparency and having a function to diffuse incident light. The second substrate is provided so as to face the second surface of the first substrate.