A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall defining inflow cells includes partition wall parts making up sides of polygon that is sectional shape of each cell, the partition wall parts each having a surface that is a face defining the inflow cell, the partition wall part is either a first partition wall part loaded with the exhaust-gas purifying catalyst on the surface so that a percentage of the area loaded therewith exceeds 10%, or a second partition wall part loaded with the exhaust-gas purifying catalyst so that a percentage of the area loaded therewith is 10% or less, and the partition wall is configured to include one or more the first partition wall parts and one or more the second partition wall parts as the partition wall parts.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion. The partition wall defining outflow cells includes an exhaust-gas purifying catalyst at least at a part of a region of 0 to 80% of a thickness of the partition wall and includes a portion that does not include the exhaust-gas purifying catalyst in a region of exceeding 80% and being 100% or less of the thickness of the partition wall, and the partition wall defining the inflow cells is not loaded with the exhaust-gas purifying catalyst on the surface, or is loaded with the exhaust-gas purifying catalyst so that a percentage of a ratio of an area of a range loaded with the exhaust-gas purifying catalyst to a surface area of the partition wall defining the inflow cells is 10% or less.

A pillar-shaped honeycomb structure filter including a plurality of first cells and a plurality of second cells, the first cells and the second cells being alternately arranged adjacent to each other with a porous partition wall interposed therebetween, wherein a ceramic porous film, in which an average film thickness T (unit: μm) is 2 to 50 μm, a porosity P (unit: %) is 65 to 90%, and the average film thickness T and the porosity P satisfy a relational expression of 0.36T+60≤P≤0.75T+72, is formed on a surface of each of the first cells.

A ceramic filter having a pillar-shaped honeycomb structure, wherein when observing a plurality of pores from a surface of partition walls with a laser microscope and plotting an equivalent circle diameter (μm) of each pore on an X-axis and a pore depth (μm) of each pore on a Y-axis on a two-dimensional coordinate system, a slope of a regression line (y/x) obtained by a least squares method in a range of 20≤x≤40 is 0 to 0.20, an average value of the pore depth of the plurality of pores is 2.5 μm to 5.0 μm, and a number density of the plurality of pores is 600/mm.sup.2 to 2450/mm.sup.2.

A honeycomb structure comprising a pillar-shaped honeycomb structure body having a porous partition wall disposed so as to surround a plurality of cells, wherein let that A denotes an absolute value of open frontal area (%) in a plane of the honeycomb structure body orthogonal to the extending direction of the cells and P denotes an absolute value of porosity (%) of the partition wall, the honeycomb structure has a value represented by the following expression (1) that is 0.05 to 0.12, let that D denotes an average pore diameter (m) of the partition wall and G denotes a geometric surface area (mm.sup.2/mm.sup.3) of the partition wall, the honeycomb structure has a value represented by the following expression (2) that is 8 to 50 (μm×mm.sup.2/mm.sup.3), and the honeycomb structure has a hydraulic diameter of the cells that is 1.1 mm or more,

(1−A/100)×(1−P/100),  Expression (1)

D×G.  Expression (2)

The honeycomb structure is equipped with a pillar-shaped honeycomb structure body having a porous partition wall that defines a plurality of cells extending from an inflow end face to an outflow end face and serving as a through channel of a fluid and a circumferential wall placed to surround the circumference of the partition wall. The honeycomb structure body has, in a face orthogonal to an extending direction of the cells of the honeycomb structure body, a circumferential cell structure, a center cell structure, and a boundary wall placed at a boundary between the circumferential cell structure and the center cell structure and incomplete cells of 5% or more to 50% or less of the total number of the incomplete cells of the center cell structure is communicated with incomplete cells of the circumferential cell structure with each other.

The honeycomb structure includes a pillar-shaped honeycomb structure body that includes a porous partition wall. When the thickness (μm) of the partition wall is defined as T.sub.1 and, among pores formed in the partition wall, the value of an average pore diameter (μm) of specific pores whose pore diameters measured by a mercury press-in method are 20 to 100 μm is defined as D.sub.(20 to 100), T.sub.1/D.sub.(20 to 100) that is a value obtained by dividing T.sub.1 by D.sub.(20 to 100) is not less than 2.4, a ratio of a pore volume of the specific pores to an overall pore volume of the partition wall is 5 to 45%, and a ratio of a pore volume of large pores whose pore diameters are not less than 100 μm to the overall pore volume of the partition wall is not more than 5%.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall is composed of a material containing cordierite as a main component thereof, porosity of the partition wall measured by a mercury press-in method is 60 to 68%, an average pore diameter of the partition wall measured by a mercury press-in method is 8 to 12 and in a pore diameter distribution which indicates a cumulative pore volume of the partition wall measured by a mercury press-in method, with a pore diameter (μm) on an abscissa axis and a log differential pore volume (cm.sup.3/g) on an ordinate axis, a first peak that includes a maximum value of the log differential pore volume has a pore diameter value of 10 μm or less, the pore diameter value corresponding to a ⅓ value width of the maximum value.

A honeycomb structure includes a honeycomb segment bonded member including; a plurality of prismatic columnar shaped honeycomb segments; and a bonding layer bonding the segments, wherein one honeycomb segment has a bulge on one side face, extending in an axial direction, another honeycomb segment has a recess on one side face, extending in the axial direction, the one honeycomb segment and the another are disposed adjacent and bonded to each other via the bonding layer with the bulge inserted in the recess, length of the bulge is smaller than length of the one side face of the one honeycomb segment, length of the recess is smaller than length of the one side face of the another honeycomb segment, a base part of the bulge is defined with a bent side face, an angle between an imaginary bottom face and the bent side face of the bulge being 60° or more.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall is composed of a material containing cordierite as a main component thereof, porosity of the partition wall measured by a mercury press-in method is 60 to 68%, an average pore diameter of the partition wall measured by a mercury press-in method is 13 to 18 μm, and in a pore diameter distribution indicating a cumulative pore volume of the partition wall measured by a mercury press-in method, with a pore diameter (μm) on an abscissa axis and a log differential pore volume (cm.sup.3/g) on an ordinate axis, a first peak including a maximum value of the log differential pore volume has a pore diameter value of 15 μm or less, the pore diameter value corresponding to a ⅓ value width of the maximum value.