Plugged honeycomb structure

A plugged honeycomb structure;

• comprising a honeycomb structure having porous partition walls defining and forming a plurality of cells communicating between two end faces, and a circumferential wall formed integrally with the partition walls,
• wherein the cells comprise partial cells positioned in an outermost circumferential portion of the honeycomb structure and being partially in contact with the circumferential wall, and normal cells other than the partial cells,
• as to the normal cells, a plugging portion is formed in one end portion of each normal cell in such a plugging pattern that the two end faces of the honeycomb structure show complementary checkered patterns, and as to the partial cells, in the partial cells in which the plugging portion is to be formed in one end portion thereof to follow the plugging pattern, the plugging portion is not formed in at least a part of the partial cell in which an area ratio obtained by Equation (1) is smaller than 80%, and
• the number of the partial cells, which the cells having an area ratio of 80% or more obtained by Equation (1), of 95% or more with respect to the number of all the partial cells each having 80% or more of the area ratio at which the plugging portion is to be formed in the one end portion thereof to follow the plugging pattern are provided with the plugging portions formed therein:
• the area ratio(%)=an area of the partial cell/an area of the normal cell×100 (1).