Provided is a resin panel produced such that the positioning of a reinforcing material can be precisely done, rattling movement is prevented and distortion by molding shrinkage is not caused because the reinforcing materials are maintained in the foam.A resin panel is a hollow double-wall structure including a front wall, a back wall and a peripheral wall joining the front wall and back wall together. The peripheral wall of the resin panel has a welded part on its entire periphery. Within a hollow part is inner packed a foam made of a thermoplastic resin that is formed in advance in the substantially the same shape as the shape of the space within the hollow part. The foam is welded on the inner wall faces of the front wall and back wall of the resin panel. In the foam are formed accommodation parts for accommodating reinforcing materials. The reinforcing materials are lengthwise. The foam intervenes between the ends of both of the reinforcing materials and the peripheral wall.