A honeycomb structure includes a plurality of prismatic columnar shaped honeycomb segments; a bonding layer bonding side faces of the honeycomb segments; and a circumferential wall disposed to surround a honeycomb segment bonded body having the honeycomb segments arranged in a grid pattern and bonded with the bonding layer, wherein the honeycomb segments has a porous partition wall disposed to surround a plurality of cells, the cells in other than outermost circumference have a hexagonal shape in a section orthogonal to the cell extending direction, the honeycomb segments include first and second honeycomb segment, the second honeycomb segment is different from the first in at least one of: a shape in the section; a size; and an arrangement direction of the cells and an extended line of one diagonal line imaginarily depicted in the cells in the first honeycomb segment and that in the second are configured to be orthogonal.