Patent ID: 7285214

Claim:
A honeycomb structure comprising: two end surfaces consisting of first and second end surfaces on respective sides of the honeycomb structure; a porous body in which a plurality of fluid channels extending to the second end surface from the first end surface are formed; and plugging members for plugging end portions of the porous body, the end portions having predetermined lengths from the end surfaces of the fluid channels, the fluid channels comprising first fluid channels whose end portions on the side of the second end surface are plugged by the plugging members and which are opened in the first end surface without being plugged by the plugging members, and second fluid channels whose end portions on the side of the first end surface are plugged by the plugging members and which are opened in the second end surface without being plugged by the plugging members, wherein one or more of the first fluid channels are formed in a shape in which an opening area S 1 in the first end surface is larger than a sectional area S 2 vertical to a central axis in a position in a predetermined depth from the first end surface and in which a sectional area S 3 vertical to the central axis in a middle between the first end surface and the position in the predetermined depth gradually decreases to the area S 2 from the area S 1 , and wherein a part of the porous body constituting an inner wall of the first fluid channel and extending to the position in the predetermined depth from the first end surface is removed, and the inner wall of the first fluid channel comprises the plugging member for plugging the end portion of the adjacent second fluid channel on the first end surface side instead of the removed part of the porous body.