Abstract: In a method for treating a combustion exhaust gas from a waste burning facility, the exhaust gas has its temperature lowered to 180-230.degree. C., in a temperature lowering unit, is freed of dust in a dry dust collector, passed through a dioxin and NOx removing unit using a vanadium oxide-based catalyst and, thereafter, the exhaust gas at 180-230.degree. C. is further passed through a heat exchanger to effect heat recovery. The vanadium oxide-based catalyst is a vanadium oxide alone or the combination thereof either with an oxide of at least one element selected from the group consisting of molybdenum, tin, yttrium, boron and lead or with gold. In addition, a tungsten oxide may be used. These catalysts are preferably carried on titania for use. The method and an apparatus for implementing it require a simple system configuration and yet assure high thermal efficiency while achieving efficient removal of dioxins and nitrogen oxides.