A honeycomb structure 1 comprising a honeycomb segment bonded body 10 having a number of honeycomb segments 2 integrated on each bonding planes via bonding material layers 9 has a structure so that a number of cells 5 providing fluid flow channels are disposed in parallel in the direction of center axis thereof. The honeycomb structure 1 is constructed so that the porosity of an outer portion of the bonding material layers 9 (an area from the interface with the honeycomb segment-bonding plane to a point apart from that interface by a distance equivalent to 20% of the entire layer thickness) is smaller than the porosity of a central portion located inward of the outer portion, and so that the bonding material layers 9 have a compression Young's modulus along the Z-axis of 5 to 100 MPa.