A honeycomb structure having multiple through holes includes at least ceramic particles and an inorganic binder. A wall thickness of each wall between adjoining through holes, on which a catalyst component is carried, is designed to be not greater than about 0.25 mm. The honeycomb structure satisfies a relation of Y≧250×X+22500 (50≦X≦80), where X denotes an aperture ratio (%) of a honeycombed face of the honeycomb structure perpendicular to the multiple through holes and Y denotes a specific surface area per unit volume (m2/L) of the honeycomb structure.