There is provided a honeycomb structure including a plurality of honeycomb segments having porous partition walls separating and forming a plurality of cells functioning as fluid passages and an outer peripheral wall located in the outermost periphery. The first cells open in an end portion on one side and plugged in the other end portion on the other side and the second cells plugged in the end portion on the one side and open in the other end portion on the other side are alternately disposed. The first cells have an area larger than that of the second cells in a cross section perpendicular to the central axial direction. The outer peripheral wall has protruding portions along an external shape of the first cells and depressed portions along an external shape of the second cells. The honeycomb segments are bonded together with a bonding member.