A honeycomb structure obtained by bonding, into one piece, a plurality of honeycomb segments (2) each having a plurality of passages (6) surrounded by cell walls and extending in the axial direction of the segment. In the honeycomb structure, a material A (3) having compressive elasticity is provided at least at a portion of the gaps formed by each two faces of adjacent honeycomb segments (2). A honeycomb structure assembly (8) obtained by providing a material B (5) having compressive elasticity on the outer peripheral portion of the above honeycomb structure in a compressed state and thereby compression-holding the honeycomb structure in a metallic container (11). The honeycomb structure and the honeycomb structure assembly have good durability and resistance to heat or vibration, applied during their use.