Provided is a resin panel without warpage, in which weight reduction and high rigidity of the resin panel have been promoted. The resin panel (1) according to an aspect of the present invention is a resin panel (1) having a back wall (3), a front wall (2) facing the back wall (3) with a gap therebetween, and ribs (3a) formed by having portions of the back wall (3) depressed toward the front wall (2) and welded to the inner surface of the front wall (2), characterized in that the back wall (3), the front wall (2) and the ribs (3a) are configured by mold-clamping, in a split mold, a first molten resin in a molten state and incorporating a plate-shaped filler, which constitutes the back wall (3), and a second molten resin in a molten state and incorporating a plate-shaped filler, which constitutes the front wall (2), the first molten resin and the second molten resin having been extruded and flowed out from an extrusion apparatus, and the longitudinal direction (3a1) of the ribs (3a) is non-parallel to the direction of flow of the first molten resin and the second molten resin.