Patent ID: 7811351

Claim:
A pillar-shaped honeycomb structural body comprising: a first end face and a second end face substantially parallel to each other; and a peripheral surface connecting the first end face and the second end face, wherein: the first end face and the second end face have similar peripheral shapes; a contour of the peripheral surface is a curved line or a combination of a linear line and a curved line; a sectional area of the honeycomb structural body parallel to the first end face continuously decreases from the first end face toward the second end face; and a taper rate P satisfies 1<P ≦approximately 4%, the taper rate P being expressed by the following formula (1) taper rate P (%)=( D 1- D 2)/(2 L )×100 formula (1) where a maximum width of the first end face is D 1 , a maximum width of the second end face is D 2 , and a distance between the first end face and the second end face is L.