An exhaust gas treating device includes a honeycomb structure including an inner honeycomb structure body including a honeycomb substrate having porous inner partition walls and a circumferential wall disposed at a circumference of the honeycomb substrate, an outer honeycomb structure body disposed at a position which surrounds a part of a circumference of the inner honeycomb structure body and is away from the inner inflow end face, and plugging portions; and a can member storing the honeycomb structure. The can member includes an inflow tube and a barrel portion which is continuous with the inflow tube, and in the barrel portion an outlet is formed, the honeycomb structure is stored in the can member in a state of having a clearance between a second end face and the can member and having a clearance between the outer outflow end face and the can member.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein, in a pore diameter distribution of the partition wall, in the case where the pore diameter (m) whose cumulative pore volume is 10% of the total pore volume is denoted by D10, the pore diameter (m) whose cumulative pore volume is 50% of the total pore volume is denoted by D50, and the pore diameter (m) whose cumulative pore volume is 90% of the total pore volume is denoted by D90, all of the following equations (1) to (6) are satisfied.
8.4 m<D10(1)
17.5 m<D50<24.0 m(2)
D90<55.2 m(3)
(log D90log D10)/log D50<0.60(4)
log D90/log D50<1.30(5)
log D50/log D10<1.38(6)

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 R1.0609e{circumflex over ()} (4.7057T) is satisfied.

A honeycomb filter comprising a pillar-shaped honeycomb structure having a porous partition wall disposed so as to surround a plurality of cells which serve as a fluid through channel extending from an inflow end face to an outflow end face and a porous plugging portion provided at either an end on the inflow end face side or an end on the outflow end face side of the cell, wherein in a processed image obtained by binarizing an electron microscope image of a visual field area of 480 m640 m of the plugging portion, the plugging portion is composed of a plurality of particles, and the number of the particles having an area of 0.25 m.sup.2 or more is 1000 or more and 3500 or less.

A cement mixture for applying to a ceramic honeycomb body that includes: (i) inorganic ceramic particles; (ii) an inorganic binder; (iii) an organic binder containing a hydrophilic polymer and a hydrophilic additive comprising a polymer with a different composition than the composition of the hydrophilic polymer, the additive having a weight average molecular weight (M.sub.w) of at least 1,000,000 g/mol; and (iv) an aqueous liquid vehicle.

A honeycomb filter includes a honeycomb structure having a porous partition wall and a plurality of plugging portions, wherein a porosity of the plugging portion is 40 to 60%, a central plugging portion having a plugging length of 5 mm or more and an outer peripheral plugging portion having the plugging length of less than 5 mm are disposed, an average plugging length L1.sub.(Ave) is 5 mm or more and 10 mm or less, an average plugging length L2.sub.(Ave) is 2 mm or more and less than 5 mm, a difference between L1.sub.(Ave) and L2.sub.(Ave) is 2 to 6 mm, a ratio of an average radius of the center part to an equivalent circle radius of the end face is 0.2 to 0.5, the plugging portion is composed of a plurality of particles, an average value of an equivalent circle diameter of each particle is 3 to 5 m, and a particle density is 750 to 1250 particles/mm.sup.2.