To effectively use a porous molding for a reclaimed land liquefaction preventing material and a building material and for soil amelioration, etc., by molding/ drying a powder or solid waste as a raw material to give a molding and reductively or oxidatively baking the molding so as to adjust the amount and the size of pores.

Incinerated ash such as fly ash, stone powder of quarry, sludge, clay, waste glass or other industrial by-products are used as raw materials. The molding is carried out by pressing powder or a solid with molds, mixing the powder or the solid with another raw material and pressing the mixture and making the powder or the solid into a slurry and pouring it into a mold. The drying is performed at normal temperature to at 200°C. The obtained molding is adjusted to the proper amount and the size of pores by controlling the heating temperature, the heating time and the heating rate of heating conditions by heating the molding to 1,300°C for 15 hours, etc., Then, the molding is naturally cooled. Otherwise, the molding is quenched and the block lump can be naturally pulveniged. The baking is carried out by using oxidative baking and reductive baking. The baked material is selected by a purpose such as sandstone (water absorption), vitrification, vitrification and poremaking, etc.