This method for producing a light control panel used in an optical image forming device includes: a step of forming a laminate 22 by laminating a plurality of transparent plate materials 20 having the same thickness while alternately shifting them by a predetermined length in the width direction so as to form protruding portions 21; a step of forming light-reflecting layers 13 at least on facing surfaces 16 of the adjacent protruding portions 21; a step of filling gap regions 26 between the adjacent protruding portions 21 with a transparent resin 27; a step of cutting and separating the protruding portions 21 integrated at each side of the laminate 22 from a laminated body 28 thereby making preforms 29, 30 for the light control panels 10, 11; and a step of flattening both end surfaces of each of the preforms 29, 30 in the width direction.