To provide a sealed honeycomb structure which can be simply regenerated in a low cost, at a low energy consumption and in a short time by an existing regeneration system not subjected to any change.

The sealed honeycomb structure 31 is one comprising a honeycomb structure 6 having partitions 2 made of a porous material and having many cells 4 separated from each other by the partitions 2 and serving as fluid passageways and a seal member 8 that seals the openings of some cells 4 of the honeycomb structure 6 and further comprising a narrowing part 16 that blocks part of each opening (non-sealed opening) remaining unsealed with the seal member 8 of cells 4 to reduce the opening area of each of the non-sealed openings so that it may be smaller than the passageway cross-sectional area of each cell 4.