Abstract: A catalytic converter has a honeycomb structure, a casing and a supporting mat. A reinforced section is formed in at least a second end section of the honeycomb structure, from which exhaust gas is discharged to the outside of the honeycomb structure. The reinforced section has a denser structure than a general section excepting a formation section of the reinforced section in the honeycomb structure. Exhaust gas is introduced into the inside of the honeycomb structure from the first end section. The exhaust gas is discharged from the second end section to outside of the honeycomb structure. A stepped section is formed in the reinforced section. The general section has a porosity within a range of 45 to 70%, and more preferably a range of 45 to 65%. The reinforced section has a porosity within a range of 5 to 35%.

Abstract: A honeycomb structure body has a honeycomb base body and a pair of electrodes composed of conductive ceramic layers and intermediate layers. The honeycomb base body made of porous ceramics containing SiC is comprised of a cell formation part and an outer peripheral part. The outer peripheral part covers the cell formation part. Each electrode is comprised of a conductive ceramic layer and an intermediate layer. The conductive ceramic layers containing SiC, Si and C are formed at two opposite positions on the outer peripheral part observed from a diameter direction. The intermediate layers containing SiC, Si and C are formed in the outer peripheral part at the parts which face the conductive ceramic layers. The honeycomb structure body satisfies a relationship of 0.5?t/T?1, where “t” indicates the thickness of the intermediate layer and “T” indicates the thickness of the outer peripheral part.