A method of manufacturing a modifed wood material can fix within a raw wood material an insoluble, non-flammable inorganic compound with a highly efficient reaction achieved between cations and anions by sequentially immersing the raw wood material at least three times alternately in each of, and different one from that employed immediately before of a first water-soluble inorganic substance solution containing cations and a second water-soluble inorganic substance solution containing anions.
