A panel member for a cyclorama includes a concavo-convex body having integrally-formed first and second side portions with an intermediate portion therebetween. The first side portion, the second side portion, and the intermediate portion have a radius of curvature in a Y-Z plane, and the first and second side portions have a radius of curvature in an X-Y plane that is different from the radius of curvature in the Y-Z plane to uniformly reflect or diffuse sound and light incident on the panel member.