The object of the present invention is to provide a method for the manufacturing of a wood cement board in which the curing of the cement can be smoothly carried out even if the wood reinforcement used originates from a sort of wood containing a large amount of cement curing inhibitor. To attain said object, the present invention provides a method for the manufacturing of a wood cement board including; scattering an ingredient wherein a sodium alum produced from aluminum sulfate and sodium sulfate, and sodium silicate are added to a mixture containing a cementitious inorganic powder and a wood reinforcement on a base panel to form a mat, then primarily curing the said mat by pressing and heating it under its moist points and, then curing the primarily cured mat at room temperature or in an autoclave. In the method, the aluminum sulfate and sodium silicate in the sodium alum improve the primary curing strength of the mat, with sodium sulfate improving the final curing strength of the mat.