A method for producing a heat-resisting compound oxide in which oxide particles are made to carry fine particles having a smaller particle diameter than that of said oxide particles. Said oxide particles or their precursor particles are charged to a potential inverse to that of said fine particles or their precursor particles so that said oxide particles adsorb said fine particles, and are then sintered to carry said fine particles. Thus, the fine particles can be homogeneously dispersed and firmly adhered to the surfaces of the oxide particles. As a result, the compound oxide is so excellent in heat resistance that it has little change, even subjected to a treatment such as a sintering, in the structure of the oxide particles for a carrier or in the adsorption state of the ultrafine particles, and has little thermal deterioration.