A honeycomb structure has 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. The cells include 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, and as to the partial cells, in the partial cells in which the plugging portion to be formed in one end portion thereof, the plugging portion is not formed in at least a part of a partial cell in which an area ratio obtained by Equation (1) is smaller than 80%: the area ratio(%)=an area of the partial cell/an area of the normal cell×100  (1).