Patent ID: 8609581

Claim:
A honeycomb structure comprising: porous partition walls having a large number of pores and disposed to form a plurality of cells communicating in an axial direction between two end faces of an exhaust gas inflow side and an exhaust gas outflow side; and plugged portions disposed to plug each of the cells on one of the end faces, wherein a length of each end portion of the honeycomb structure is 30% of a length of the honeycomb structure, a length of a central portion of the honeycomb structure between the end portions is 40% of the length of the honeycomb structure, both of the end portions and the central portion of the honeycomb structure each include one or more sampling regions, each sampling region including one or more sub-sampling portions, wherein, an average image maximum distance of a sampling region is an average of the largest pore diameters of the sub-sampling portions of the associated sampling region, wherein each sub-sampling region includes one largest pore diameter, wherein average image maximum distances of both of the end portions are less than average maximum distances of the central portion, and a cell hydraulic diameter (m) of the honeycomb structure and a permeability (m 2 ) of the honeycomb structure satisfy a relation of (cell hydraulic diameter) 2 /(permeability) being 2×10 3 or greater, and less than 6×10 5 , the average image maximum distance of the partition walls is 43 μM or more, and the average image maximum distance of the cells in both of the end portions in the longitudinal direction is 80% or less of the average image maximum distance of the cells in the central portion in the longitudinal direction.