A method is disclosed for manufacturing, by injection molding with use of a mold, a light guide plate in which a first region having a curvature in a first direction and a second region having a predetermined curved surface are connected. The mold includes a first member for forming the first region and a second member for forming the second region. The first member is manufactured by bending a first electroforming stamper on which a predetermined structure is formed by electroforming in a direction corresponding to the first direction.