A surface illumination apparatus is provided which includes a laser light source and a light guide plate upon which a laser beam emitted from the laser light source is incident through an end-surface portion and from which the laser beam is emitted through a main-surface portion on one side thereof. The laser beam is incident through an end-surface portion at an inclination angle to a main-surface portion on the other side which faces the one main-surface portion of the light guide plate, undergoes a change in the optical-path direction thereof by the other main-surface portion, is incident on the one main-surface portion and is emitted as a substantially parallel beam from the one main-surface portion.