A honeycomb structure includes a porous partition wall defining a plurality of cells serving as fluid passages, an outer peripheral wall located at the outermost periphery, a first cell having one end opened and the end plugged, and a second cell having the one end plugged and the other end opened. The first cells and the second cells are disposed alternately, and the area of the first cells is larger than that of the second cells in a cross section perpendicular to a center axis. The thickness of the partition wall that forms at least one cell from the outermost periphery in the outer peripheral section is 1.1 to 3.0 times the thickness of the partition wall in the center section.