Abstract: A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall arranged to surround a plurality of cells and a plugging portion, wherein the sectional shape of inflow cells is octagonal and the sectional shape of outflow cells is quadrangular, the area ratio of a sectional area of the outflow cell to the sectional area of the inflow cell is 1.60-1.90, in the honeycomb structure body, the central part of the section orthogonal to the extending direction of the cells is composed of a cell straight region in which the cells extend in a straight line and the outer periphery of the section is composed of a cell curvature region in which the cells extend in a curved manner, and the percentage of the ratio of the curvature height of the cell curvature region to the total length of the honeycomb structure body is 1.00-3.00%.

Abstract: A honeycomb filter includes a honeycomb structure having a porous partition wall disposed to surround a plurality of cells and a plugging portion provided to seal either one end of the cells, wherein the cells having the plugging portion at ends on the outflow end face side and open on the inflow end face side are inflow cells, the honeycomb structure further includes a trapping layer for trapping particulate matter in exhaust gas on the inner surface of the partition wall surrounding the inflow cells, the trapping layer is a porous layer in which a plurality of non-oxide particles are bonded via an oxide, a thickness of the oxide that bonds adjacent non-oxide particles is 0.077 ?m or more, and when an average particle diameter of the non-oxide particles constituting the trapping layer is R(?m) and a thickness of the oxide is T(?m), a relation of R?1.0609e{circumflex over (?)} (4.7057×T) is satisfied.

Abstract: A honeycomb filter including: a honeycomb structure having a porous partition wall provided surrounding a plurality of cells; and a plugging portion disposed to seal either one end portion on the inflow or the outflow end face side of the cells, wherein the cell in which the plugging portion is provided at the outflow end face side and the inflow end face side is open is defined as an inflow cell, the cell the plugging portion is provided at the inflow end face side and the outflow end face side is open is defined as an outflow cell, the honeycomb structure further has a trapping layer for the particulate matter on an inner surface side of the partition wall, the trapping layer includes a portion composed of a sintered body of CeO2 particles on at least a surface layer, and the average particle diameter is 1.1 ?m or less.

Abstract: A honeycomb filter including: a honeycomb structure having a porous partition wall provided surrounding a plurality of cells; and a plugging portion disposed to seal either one end portion on the inflow or the outflow end face side of the cells, wherein the cell in which the plugging portion is provided at the outflow end face side and the inflow end face side is open is defined as an inflow cell, the cell the plugging portion is provided at the inflow end face side and the outflow end face side is open is defined as an outflow cell, the honeycomb structure further has a trapping layer for the particulate matter on an inner surface side of the partition wall, the trapping layer includes a portion composed of a sintered body of CeO2 particles on at least a surface layer, and the average particle diameter is 1.1 ?m or less.