A honeycomb structure includes at least one honeycomb unit (100) having multiple through holes (122) provided in parallel in a longitudinal direction and separated by a cell wall (124), wherein the at least one honeycomb unit (100) includes a pair of electrodes (160A,160B), and the cell wall (124) has pores filled with a substance directly under a formation region of the electrodes (160A,160B), the substance having an electrical resistivity lower than the electrical resistivity of the material forming the at least one honeycomb unit (100).