Ceramic honeycomb filter

A ceramic honeycomb filter comprising pluralities of flow paths partitioned by porous cell walls, a fluid entering one end of said filter and flowing through said porous cell walls being discharged from the other end of said filter;

• pluralities of said flow paths comprising intake flow paths which are open on said one end side and sealed on said other end side, and discharge flow paths which are sealed on said one end side and open on said other end side;
• and
• in a cross section perpendicular to the longitudinal direction of said flow paths,
• (a) cross section areas of said intake flow paths being larger than those of said discharge flow paths;
• (b) said intake flow paths and said discharge flow paths having octagonal cross section shapes with four-fold rotation symmetry, such that all flow paths in the ceramic honeycomb filter having octagonal cross section shapes have four-fold rotation symmetry;
• (c) said intake flow paths and said discharge flow paths being alternately arranged in a first direction and a second direction perpendicular to said first direction, such that their opposing sides are parallel via said cell walls;
• (d) an opening ratio of said intake flow paths being 45-60%;
• (e) number of said flow paths per cm2 being 30-60;
• (f) a thickness t1 of a cell wall between an intake flow path and a discharge flow path adjacent to that intake flow path being 0.150-0.260 mm;
• and
• (g) a thickness t2 of a cell wall between adjacent intake flow paths meeting 1.175<t2/t1<1.6.