The manufacturing method includes a step of mixing a coarse particle zeolite, a fine particle zeolite, and a raw material of an inorganic bonding material to prepare a zeolite raw material; a step of forming the prepared zeolite raw material into a honeycomb shape to prepare a honeycomb formed body; and a step of firing the prepared honeycomb formed body to prepare the honeycomb structure. In the step of preparing the zeolite raw material, as the coarse particle zeolite, a chabazite type zeolite having a specific average particle diameter, the fine particle zeolite having a specific average particle diameter, the raw material of the inorganic bonding material which includes at least basic aluminum lactate is used.

A honeycomb structure includes honeycomb segments each having a porous partition wall defining a plurality of cells, and includes a porous bonding layer containing a crystalline anisotropic ceramic and disposed so as to bond side surfaces of the honeycomb segments to each other. A ratio of a pore volume (cc/g) of a fine pore defined as a pore in the bonding layer having a pore diameter of 10 μm or more and less than 50 μm with respect to a pore volume (cc/g) of a coarse pore defined as a pore in the bonding layer having a pore diameter of 50 μm or more and 300 μm or less is from 2.0 to 3.5, the pore volume of the fine pore is from 0.15 to 0.4 cc/g, and the pore volume of the coarse pore is from 0.05 to 0.25 cc/g.

A ceramic formed body extrusion method for forming a ceramic formed body having a wall-shaped or plate-shaped formed portion by using an extrusion die provided with a slit for extrusion of a ceramic formed body from a raw material for forming, the slit including a slit former stage unit located on an upstream side in an extrusion direction in the extrusion and a slit latter stage unit located on a downstream side in the extrusion direction, the slit latter stage unit having a width of three to 27 times a width of the slit former stage unit, and by extruding a raw material containing a first particle having an aspect ratio of two or more and less than 300 such that the raw material passes though the slit former stage unit of the extrusion die and then passes through the slit latter stage unit.

The cutting method of a honeycomb formed body includes an end face cutting step of cutting both end faces of the ceramic honeycomb formed body before fired, by use of blade type rough-cutting grinding wheels in which coarse abrasive grain layers are formed; a honeycomb formed body rotating step of rotating the honeycomb formed body round a rotation axis which is a central axis perpendicular to the end faces of the honeycomb formed body; and an end face finishing step of disposing two finish-polishing grinding wheels via a predetermined distance so that finishing abrasive grain layers formed in the finish-polishing grinding wheels face each other, rotating the finish-polishing grinding wheels round a rotary shaft which is a central shaft of the finish-polishing grinding wheels, and moving the honeycomb formed body to pass the honeycomb formed body between the two finish-polishing grinding wheels, thereby finish-polishing cut surfaces which are cut.

A manufacturing method includes a mixing step, a kneading step of kneading a wet mixture, a liquid adding step of further adding a liquid to a kneaded material, a forming step of extruding a forming material of which viscosity is adjusted into a honeycomb formed body, a drying step of drying the honeycomb formed body, and a dimension measuring step of measuring a dry dimension of a honeycomb dried body that has been dried, where in the liquid adding step, the amount of the liquid to be added is adjusted based on the result of measuring the dry dimension of the honeycomb dried body.

A honeycomb structure has partition walls defining a plurality of polygonal cells which become through channels for a fluid, a structure end face vertical to an axial direction has at least two cell regions possessing mutually different cell structures and surrounded by circumferential portions, and in the cell regions adjacent to each other, to first partition walls of a first cell structure of one first cell region, second partition walls of a second cell structure of the other or second cell region are tilted.

A honeycomb structure has a pillar-shaped honeycomb structure body having porous partition walls which defines cells which forms a passage of liquid extended from an inflow end face toward an outflow end face, a circumferential wall arranged to surround a circumference of the partition walls. The honeycomb structure body has an outermost circumference cell structure including a complete cell arranged at the outermost circumference of the honeycomb structure body, a center cell structure formed by the cells arranged at a center part at an inner side to the outermost circumference cell structure, and a boundary wall arranged at a boundary part between the outermost circumference cell structure and the center cell structure. The outermost circumference cell structure and the center cell structure are formed as different structures to each other, and a thickness of the boundary wall is set to be thicker than a thickness of the circumferential wall.

A honeycomb structure includes a honeycomb structure body including porous partition walls defining a plurality of cells serving as fluid passages extending from an inflow end face to an outflow end face. The partition walls have a porosity of 45 to 65%; the open frontal area of the pores having an equivalent circle diameter of 10 μm or more, of the pores open on the surface of each partition wall, is 20 to 50%; the pore density of the pores having an equivalent circle diameter of 10 μm or more is 200 to 1,000 pores/mm.sup.2; the median opening diameter of the pores having an equivalent circle diameter of 10 μm or more is 40 to 60 μm; the circularity of the pores having an equivalent circle diameter of 10 μm or more is 1.8 to 4.0; and the partition walls have a wet area of 16,500 μm.sup.2 or more.

The manufacturing method of the honeycomb structure includes a mounting step of mounting an extruded honeycomb formed body on a firing setter disposed on a shelf plate, and a firing step of firing the honeycomb formed body mounted on the firing setter to form the honeycomb structure, and in the mounting step, the firing setter is used in which a value obtained by dividing an area of a formed body end face of the honeycomb formed body by an area of a honeycomb mounting surface of the firing setter which faces the formed body end face and at least a part of which comes in contact with the formed body end face is in a range of 2.5 to 20.0.

The manufacturing method of the honeycomb structure includes a raw material preparing step of adding the powder of porous silica as the inorganic pore former to a forming raw material and kneading the forming raw material to prepare the kneaded forming raw material, an extruding step of extruding the obtained forming raw material to form a honeycomb formed body, and a firing step of firing the extruded honeycomb formed body to form a honeycomb structure containing a cordierite component, and an amount of oil to be absorbed by the porous silica to be added to the forming raw material is in a range of 50 to 190 ml/100 g, and a BET specific surface area of the porous silica is in a range of 340 to 690 m.sup.2/g.