Abstract: A honeycomb structure includes aluminum titanate, cell walls, and pore portions. The cell walls extend along a longitudinal direction of the honeycomb structure to define cells between the cell walls. The pore portions have an average pore diameter of about 10 ?m to about 20 ?m. A length of a longest pore portion among the pore portions in a binary image including substrate portions and the pore portions is about 8 times or less of the average pore diameter. The binary image is converted from a microscopic image of a cross section of the cell walls in parallel with the longitudinal direction. The length is measured along a line drawn in a direction perpendicular to a thickness direction of the cell walls.

Abstract: A method for manufacturing a honeycomb structure includes molding a wet mixture containing an aluminum titanate powdery material to form a honeycomb molded body. The aluminum titanate powdery material contains about 40% to about 60% by mass of Al2O3, about 30% to about 50% by mass of TiO2, and about 1% to about 15% by mass of (MgO+SiO2). The honeycomb molded body has cells provided substantially in parallel with one another in a longitudinal direction of the honeycomb molded body. The honeycomb molded body is fired at a temperature of about 1200° C. to about 1700° C.