A honeycomb structure comprising porous partition walls which form, by surrounding, a plurality of cells extending between the two ends faces of the honeycomb structure, and an outer wall formed integrally with the partition walls. The cells consist of partial cells of outermost peripheral portion, having incomplete cell sections, which are located at the outermost peripheral portion of the honeycomb structure and are in partial contact with the outer wall, and complete cells having a complete cell section, other than the partial cells of outermost peripheral portion. In the complete cells, a plugged part is formed at one end of each complete cell so that each end face of the honeycomb structure shows a checkerwise plugging pattern. In the partial cells of outermost peripheral portion to be plugged according to the above-mentioned plugging pattern, part of them is plugged in the entire length and formed integrally with the outer wall and remaining cells have each a plugged part only at one end.