An illumination device capable of suppressing formation of a double image in three-dimensional display, and a display unit including the illumination device are provided. In a light modulation device bonded to a light guide plate, a scattering region that scatters light propagating within the light guide plate, and a transmissive region that allows light propagating within the light guide plate to pass therethrough are formed through control of an electric field. The scattering region scatters light to generate linear illumination light. A reflector is provided directly below the light modulation device. The reflector reflects light, which is part of the scattered light generated in the scattering region and is emitted to a reflector side, to generate reflected light to be focused directly below the scattering region.