A honeycomb structure comprising a plurality of columnar honeycomb segments in which two kinds of plural through-holes different in end face area are formed side by side by being surrounded by partition walls, each honeycomb segment having, at one end face, an inlet side of high opening ratio, wherein through-holes of smaller end face area are plugged and, at other end face, an outlet side of low opening ratio, and wherein through-holes of larger end face area are plugged, the plurality of honeycomb segments being bonded to each other via a bonding material in the longitudinal direction of each honeycomb segment. The Young's modulus of the bonding material when sintered is smaller than that of each honeycomb segment when sintered, and the bonded width of the bonding material is larger at the outlet side of honeycomb structure than at the inlet side is presented.