A honeycomb structure 1 having an outer wall 7, partition walls 2 disposed inside the outer wall, and a plurality of cells 3 partitioned from one another by the partition wall 2 and extending in the axial direction, each cell having a generally rectangular cross-section shape in the direction perpendicular to the axial direction. The honeycomb structure 1 is characterized in that the honeycomb structure 1 is provided with a reinforced part 72 on a part of the outer wall 7. The honeycomb structure may exhibit excellent mechanical strength and low pressure loss.