A pillar-shaped honeycomb structure having a plurality of cells formed by laminating a plurality of lamination members with a plurality of through holes. The plurality of through holes form the plurality of cells. The lamination members are a substantially disc shaped. A plane portion, a protruding portion, or a cut-out portion is formed on a peripheral side face of the lamination member, or a rod member is inserted in at least one cell of the plurality of cells, where the rod member penetrates from one end to the other end of the cell.