Plugged honeycomb structure

A plugged honeycomb structure comprising:

• a plurality of prismatic columnar honeycomb segments;
• a bonding layer bonding side surfaces of the plurality of honeycomb segments to one another, and
• plugging portions arranged in open ends of predetermined cells in an inflow end face of each honeycomb segment and arranged in open ends of residual cells in an outflow end face thereof,
• wherein each honeycomb segment has porous partition walls arranged to surround a plurality of cells extending from the inflow end face to the outflow end face, and segment circumferential walls arranged at an outermost circumference, in a cross section of the honeycomb segment which is perpendicular to an extending direction of the cells, at least two types of cells having different shapes are formed to constitute predetermined repeated arrangement patterns,
• the cells including the plugging portions arranged on the side of the inflow end face are defined as outflow cells, and the cells including the plugging portions arranged on the side of the outflow end face are defined as inflow cells,
• the cells of the honeycomb segment include whole rim partition wall cells and partial rim circumferential wall cells,
• the whole rim partition wall cells are the cells having whole rims of the cells which are surrounded by the partition walls,
• the partial rim circumferential wall cells are the cells having rims of the cells which are surrounded by the partition walls and the segment circumferential walls,
• a shape of the cross section of each partial rim circumferential wall cell which is perpendicular to the cell extending direction includes a shape of at least a part of the whole rim partition wall cell, and
• when a value obtained by dividing an average sectional area S1in of the inflow cells by an average sectional area S1out of the outflow cells in a region where the whole rim partition wall cells are present is denoted R1s, and
• a value obtained by dividing an average sectional area S2in of the inflow cells by an average sectional area S2out of the outflow cells in a region where the partial rim circumferential wall cells are present is denoted R2s,
• a ratio of the R2s to the R1s is in a range of 1.7 times or more and 2.0 times or less.