To provide a method for reducing water content in high energy efficiency and an apparatus therefor.

(1) A charging material preheated to about 60°C is subjected to steam treatment on both sides at the beginning of operating cycle in a pressure chamber closed virtually airtightly and preheated to 100°C and by steam overheated to ≥150°C, (2) compressive pressure on the charging material higher than or equal to the pressure developed by the stacking density within the charging material is made to correspond to the steam pressure fed at a maximum about 5 to 8bar, and (3) after the temperature within the charging material reaches ≥125°C, steam jetting is terminated, and mechanically unique press pressure of as high as ≤75bar is applied to the charging material according to its granular size in order to reduce the water content thereof to a residual level of ≤20wt.%.