The present invention relates to a technique which makes a backlight used in a liquid crystal display device thin and light-weight. The present invention provides a liquid crystal display device which includes a display panel and a backlight arranged behind the display panel, wherein the backlight includes a film-like light guide member, a film-like light semi-transmissive member adhered to a first surface of the light guide member which faces the display panel in an opposed manner, a film-like reflective member adhered to a back surface of the light guide member opposite to the first surface, and a spot light source arranged at a position of the light guide member at which light is incident on the light guide member from the first surface or the back surface. A refractive index of the light semi-transmissive member is set smaller than a refractive index of the light guide member.