An aggregate with small fiber deterioration even after being held under compression under heating at about 1,000 DEG C for a long term, and a holding material of e.g. a catalyst carrier of a catalyst converter or a honeycomb body of DPE employing it, are provided. An inorganic short fiber aggregate for a holding material, which is an aggregate of inorganic short fibers having a chemical composition of from 74 to 86 mass% of an alumina component and from 26 to 14 mass% of a silica component and having a mineral composition of from 15 to 60 mass% of mullite, wherein the average fiber diameter of the aggregate is from 2 to 8 mu m, at least 99% (including 100%) of the number of the inorganic short fibers consists of fibers having fiber diameters of from 1.5 to 15 mu m, and the specific surface area is at most 10 m<2>/g. Its production process, and a holding material consisting of a sheet-shape formed product comprising the aggregate and an organic binder contained in the aggregate, wherein inorganic short fibers are employed.