Patent ID: 8496724

Claim:
A plugged honeycomb structure comprising: a columnar honeycomb substrate having porous partition walls separating and forming a plurality of cells extending from one side end face to another side end face and functioning as gas passages, plugging portions for alternately plugging opening end portions on a gas inflow side and opening end portions on a gas outflow side of the cells, and porous particulate matter (PM) trapping layers being disposed to have a membrane shape on surfaces of the partition walls that define inflow cells whose opening end portions are open on the gas inflow side, and having pores with an average pore size smaller than that of the partition walls; wherein the PM-trapping layers extend up to inflow side end faces of outflow cells whose opening end portions are with plugging portions on the gas inflow side, and adjacent PM-trapping layers with the partition walls and the plugging portion therebetween are disposed so as to continue onto the inflow side end faces of the plugging portions in the outflow cells to form protruding portions having a protrusion height corresponding to 0.1 to 2 times the length of the plugging portions in the outflow cells.