The present invention aims at providing an inorganic fiber molded body that is excellent in scale resistance, thermal shock resistance and mechanical shock resistance, and prevented from suffering from shrinkage when used under high-temperature heating conditions. The inorganic fiber molded body of the present invention is produced by impregnating a needle blanket of inorganic fibers with a liquid material of a precursor of a spinel-based compound represented by the general formula: Mg x Al y O 4 wherein an atomic ratio (y/x) is not less than 2 (y/x ≥ 2); drying the thus impregnated needle blanket; and firing the dried needle blanket to convert the precursor into an oxide thereof.