A light guide plate in which the light incident on an entrance end surface is allowed to emerge from a bottom surface view a light issuing means formed on a top surface, with the direction of maximum intensity of the emerging light as measured in a plane perpendicular to the two reference planes defined by said entrance end surface and said bottom surface being within 30 degrees from the line normal to said bottom surface and wherein when the direction toward the entrance end surface away from said normal line taken as the reference is assumed to be negative, the intensity of the light leaking from the top surface at the same angle as the direction of said maximum intensity is no more than a tenth of said maximum intensity, with the incident light from the bottom surface being transmitted through the top surface; a planer light source unit having a light source adjacent the entrance end surface of the light guide plate; and a reflection-type liquid-crystal display device having a reflective layer furnished, liquid-crystal cell provided beneath the bottom surface of the planer light source unit.