A lighting device includes a light source 30, a light guide 20 provided adjacent to the light source 30 and including a light source light incident surface 21 on which light emitted by the light source 30 enters and a planar light emission surface 22 from which planar light is emitted, and an optical sheet 50 including a planar light incident surface 53 on which the planar light enters, and configured to change a traveling direction of the planar light because a light emission side of the optical sheet 50 has a shape in which plural columnar prisms 51 extending in parallel to the light source light incident surface 21 are arranged side by side. In each of the prisms 51, a distal surface has at least different two kinds of inclination angles.