PURPOSE: To provide ceramic products which are free from warpages or undulations by firing the material of inorganic fibers and inorganic powder after molding the same into plates or boxes.

CONSTITUTION: For the inorganic fiber, ceramic fibers are used for instance, and, for the inorganic powder, cordierite is used for instance. They are mixed by the weight ratio of 60/40 for instance, and, after being mixed with water, they are mixed by mixer to turn them into a slurry. The slurry is flocked by adding an organic binder of acrylic group and a cohesive agent of cationic group, and the cordierite is fixed to the ceramic fibers. When the slurry is filled into a square vessel 2 having a wire mesh 1 in the bottom and the air is drawn from under, the solid components in the slurry deposit on the wire mesh 1, and, as the drawing is further continued, a wet setter S1 can be obtained. The wet setters S1 are superposed and dried, which are fired to obtain the firing setters. When a tile 6 is placed on the top of them and fired, there will be no warpages or undulations.