An organic-inorganic composite material is disclosed wherein an inorganic compound is finely dispersed in an organic polymer matrix in nanometer order and the inorganic compound content is large. The organic-inorganic composite material has formability and flexibility of organic materials and features of various metal compounds (such as hardness, catalytic power, insulating property, semiconducting property, electronic conductivity, ionic conductivity, large specific surface area, high heat resistance, wear resistance, and dimensional stability to temperature changes or moisture absorption) at the same time.