A method of producing a product inorganic compound including: immersing a raw material inorganic compound having a volume of 10−；13 m3 or more in an electrolyte aqueous solution or an electrolyte suspension； exchanging anions in the raw material inorganic compound with anions in the electrolyte aqueous solution or the electrolyte suspension； cations in the raw material inorganic compound are exchanged with cations in the electrolyte aqueous solution or the electrolyte suspension； or including a component (that excludes water, hydrogen, and oxygen) in the electrolyte aqueous solution or the electrolyte suspension not included in the raw material inorganic compound in the raw material inorganic compound； and obtaining a product inorganic compound having a volume of 10−；13 m3 or more from the raw material inorganic compound.
