A honeycomb structural body includes a plurality of honeycomb units adhered to each other by interposing an adhesive layer. Each of the honeycomb units has a substantially fan shaped cross section or a substantially elliptical fan shaped cross section perpendicular to a longitudinal direction of each of the honeycomb units. First and second electrodes are provided at a part of an outer peripheral surface of each of the honeycomb units that does not face the adhesive layer and are provided at a first area between each of the honeycomb units and the adhesive layer. And/or the first and second electrodes are provided at a second area between the outer peripheral surface of each of the honeycomb units and the adhesive layer and are provided at a third area including a center of the substantially fan shaped cross section or the substantially elliptical fan shaped cross section.