A method for producing plaster plates (44), according to which two fine cardboard-covered sheets of paper (8, 9) enclose a plaster-based hydraulic binder (10) in a shaping device (13), creating a composite band (45) that is hardened on one or several hardening bands (14, 15), the edges of said hardening bands (14, 15) being provided with two bands used for tapering in the horizontal direction.