To provide a method for injecting wanted cations (of a metal) into the inside of an inorganic solid material or controlling a metal component for substituting other metal in the inside of the inorganic solid material.

This method for metal doping on an inorganic solid material is to form a sandwich electrolysis system by adhering one side of an inorganic solid material A to be brought to an object for doping with a solid electrolyte material B containing metal ions (Mn+) to be brought for doping and the outside of the solid electrolyte material B to a cathode (plate) C, while adhering the other side of the doping-objective inorganic solid material A to a solid electrolyte material containing arbitrary metal ions or a solid electrolyte material F which is an oxygen ion conductor, and electrically injecting metal ions (Mn+) included in the solid electrolyte material on the cathode side into the doping objective inorganic solid material by applying an electric current between the both electrodes. This method is applicable to the fields of various functional materials such as electric and electronic materials, etc.