A light guide plate which is made of a polymeric resin having an alicyclic structure and has recesses for reflection formed on a light reflecting surface, the recesses being so arranged that the density of the recesses increases with the distance from a light source. Each recess is preferably a V-shaped groove each having an angle of 70.degree. to 150.degree. and a depth of 1 .mu.m to 1000 .mu.m or a groove which is long and approximately perpendicular to the direction in which light is incident at any position on the light reflection surface.