The present invention provides a honeycomb structure in which a plurality of honeycomb segments each constituted by a cell structure having a plurality of cells divided from each other by partition walls and functioning as a passage for fluid and an outer wall provided at the circumference of the cell structure are bonded to each other at the outer walls by a bonding layer made of a bonding agent and converted into one piece, which honeycomb structure is characterized in that the bonding agent does not contain inorganic particles having diameters (.mu.m) of at least 1.1 times the average surface roughness Ra (.mu.m) of the outer wall, in an amount exceeding 30% by mass relative to the total of the bonding agent. In the honeycomb structure, the honeycomb segments as a constituent are strongly bonded to each other by a bonding agent and converted into one piece.