A light guide plate that uses a resin film as a material for the light guide plate, that has a reflecting or scattering pattern formed by printing, and that guides a light propagating in the film to exit and emerge from the front surface thereof. The light guide plate is thinner and highly flexible, and has high reliability and durability. A base material of the light guide plate is formed from a thermosetting polyurethane sheet with a thickness of 0.4 mm or less. When a dot pattern is formed by ink-jetting, a white UV curable ink, for which the thermosetting polyurethane exhibits a swellability such that the thermosetting polyurethane increases by 10% or more in weight as a result of being soaked in the ink for one hour at a room temperature, is used as the ink.