Gypsum boards are bent to curved shape by placing a water dampened flat rectangular gypsum board upon a resiliently bendable panel positioned below a bender shell having a wall of arcuate cylindric contour which grips a margin of the gypsum board, and rolling the bender shell upon the gripped board to produce bending. A circular cylindrical weight rolls within the bender shell to apply compressive force upon the gypsum board during the bending process.