A polariser (14) is provided on the upper side of a liquid crystal panel (10), and a light scattering member (15) and a polarised light separator (16) are provided in turn on the lower side of the liquid crystal panel (10). Of light incident on the upper side of the polarised light separator (16), a linearly polarised light component parallel to the plane of the drawings is transmitted, a linearly polarised light component perpendicular to the drawings is reflected, and for light incident on the lower side thereof, a linearly polarised light component parallel to the drawings can be emitted upwardly. When the switch is off, the external light incident on the display device is reflected by the polarised light separator (16) to obtain a bright display, and when the switch is on, the incident external light is transmitted through the polarised light separator (16) to obtain a dark display. when the switch is off, light from a light source (17) is transmitted through the polarised light separator (16) and absorbed by the polariser (12) to obtain a dark display, and when the switch is on, the light is transmitted through the polarised light separator (16) and through the polariser (14) to obtain a bright display.