Patent attributes
A honeycomb structural body is made of cordierite ceramic and composed of partition walls and cells. A cell density is changed continuously or step by step from a central section to an outer peripheral section in a radial direction. The honeycomb structural body has a relationship of M1>M2>M3, and a relationship of K1<K2. M1 is an average cell density of a first section formed from a center to not more than ⅓ R from the center. M2 is an average cell density of a second section formed within a range from ⅓ R to ⅔ R. M3 is an average cell density of a third section formed of more than ⅔ R from the center to an outer peripheral surface. K1 and K2 are average cell density change rates of the first and second sections, respectively. R is a radius of the honeycomb structural body.
