A catalyst support, a catalyst using the catalyst support and a process for producing the same are disclosed. For instance, the catalyst support includes a composite oxide powder produced by spraying and burning a W/O type emulsion, the W/O type emulsion including an aqueous solution dispersed in an organic solvent, the aqueous solution containing aluminum as a major component and at least one co-metallic element in addition to the aluminum. Thus, the catalyst support can be produced less expensively without using any expensive alkoxide. Further, due to the spraying and burning, the composite oxide powder is composed of porous hollow particles which have a very thin shell thickness of dozens of nanometers, and makes the catalyst support which is amorphous and exhibits a large specific surface area. Hence, the catalyst support can maintain the large specific surface area even after a high-temperature durability test. Furthermore, the composite oxide powder includes the co-metallic element which is composited in such a highly dispersed manner that the agglomerated sulfates are less likely to be produced. Therefore, the catalyst support is inhibited from being poisoned by sulfur.