<p>A honeycomb structure body (10) where honeycomb units (11) are bound together, with seal material layers (14) in between, and the honeycomb units (11) each have a large number of through-holes (12) arranged side-by-side oriented in the longitudinal direction with partition walls in between. The honeycomb units (11) contain at least ceramic particles, and inorganic fibers and/or whiskers. The outer peripheral surface of the honeycomb structure body (10) has surface roughness Ra of not less than 1 µm and not more than 50 µm.</p>
