<p>Honeycomb structure (1) comprising honeycomb segment junction element (10) having multiple honeycomb segments (2) integrated together on mutual junction planes via junction material layers (9), which honeycomb structure (1) has such a structure that multiple cells (5) providing fluid flow channels are aligned in parallel to each other in the direction of center axis thereof. The honeycomb structure (1) is constructed so that the porosity of an outside portion of each of the junction material layers (9) (portion extending from an interface with honeycomb segment junction plane to a point distant as much as a length corresponding to 20% of the relevant whole layer thickness) is smaller than the porosity of a central portion located inward of the outside portion, and so that the junction material layers (9) each have a compression Young's modulus along Z-axis of 5 to 100 MPa.</p>
