A lighting device for emitting light in a planar manner comprises a backlight section having non-uniformity in light emission in a plane and an optical film having an in-plane transmittance distribution compensating for the non-uniformity in light emission. The optical film has a plurality of slits allowing light to pass through and controls the in-plane transmittance distribution by varying the shapes of slit openings. Widths of the slits are fixed, closed portions are provided in a longitudinal direction, and the in-plane transmittance distribution is controlled by the ratio of the closed portions to the slits. A part of the optical film other than the slits is a light shielding layer, and a surface on the light source side of the light shielding layer scatters and reflects light. Each value in the in-plane transmittance distribution of the optical film is smaller than the reciprocal of a corresponding value in a light intensity distribution of the backlight section. A surface opposite to a surface on the light source side of the optical film has a cylindrical lens structure focused on the slits. Non-uniformity in light emission in the lighting device such as a backlight used in a liquid crystal display is eliminated at a low cost.