Abstract: A method is disclosed of molding a cementitious material within a mold having a filler material bed, the configuration of which is maintained by means of suction applied through a filter disposed within the mold frame. A shield layer can be formed upon a surface of the filler material bed having air permeability so as to impart a desirable shape thereto, and the filler material is fixed under reduced pressure conditions within the mold so as to form a molding mold, whereupon the cementitious material may be charged into the mold so as to set therein. It is also possible to achieve the method of the present invention by charging a cementitious material within a molding mold having a desirable configuration, forming a filler material bed having good air permeability with or without a shield layer disposed upon the cementitious material, and preparing a hardening mold, under reduced pressure conditions, beneath the filler material bed.