10 0 g l of gamma alumina powder and then milling the mixture was applied on a ceramic honeycomb structure having a cpsi of 600 cells inch 2 and a wall thickness of 4 0 milliinches subsequently slurry for a second layer prepared by mixing 60 0 g l of gamma alumina powder impregnated with 1 75 g l of palladium nitrate with 30 0 g l of a zirconia rich oxygen storage material was layered and applied on a first layer then slurry for a third layer prepared by mixing 40 0 g l of gamma alumina powder impregnated with 0 25 g l of platinum chloride with 40 0 g l of a ceria rich oxygen storage material was layered and applied on a second layer thereafter the coated laminate honeycomb structure was dried at a temperature of 120 u25a1 for 4 hours and then baked at a temperature of 550 u25a1 for 2 hours thereby fabricating a first catalyst the catalyst fabricating process was performed as in example 1 except that 20 of the palladium component included in the slurry for a second layer was applied to the slurry for a third layer thereby fabricating a second catalyst the catalyst fabricating process was performed as in example 1 except that 10 of the platinum component included in the slurry for a third layer was applied to the slurry for a second layer and minimum rhodium 0 05 g l was applied to the slurry for a third layer thereby fabricating a third catalyst slurry for a first layer in which 96 0 g l of gamma alumina powder impregnated with 1 75 g l of palladium nitrate and 17 6 g l of a low oxygen storage material.