A honeycomb filter comprising: a honeycomb fired body including porous cell partition walls (13, 13a, 13b, 13c) defining a plurality of cells that serve as channels of exhaust gas, exhaust gas introduction cells (12, 12A) each having an open end at an exhaust gas inlet side and a plugged end at an exhaust gas outlet side, exhaust gas emission cells (11, 11A, 11B) each having an open end at the exhaust gas outlet side and a plugged end at the exhaust gas inlet side, and an outer wall on the periphery thereof, wherein the cross-sectional shape of each exhaust gas introduction cell (12, 12A) in a plane perpendicular to the longitudinal direction thereof is entirely uniform from the end at the exhaust gas inlet side to the end at the exhaust gas outlet side excluding the plugged portion, the cross-sectional shape of each exhaust gas emission cell (11, 11A, 11B) in a plane perpendicular to the longitudinal direction thereof is entirely uniform from the end at the exhaust gas inlet side to the end at the exhaust gas outlet side excluding the plugged portion, the cross-sectional shape of each exhaust gas introduction cell (12, 12A) in a plane perpendicular to the longitudinal direction thereof is a polygon, the exhaust gas emission cells (11, 11A, 11B), except for the cells adjacent to the outer wall, are each adjacently surrounded fully by the exhaust gas introduction cells (12, 12A) across the porous cell partition walls (13, 13a, 13b, 13c), the cells adjacent to the outer wall include the exhaust gas introduction cells (12, 12A) and the exhaust gas emission cells (11, 11A, 11B), the aperture ratio of the exhaust gas introduction cells (12, 12A) of the honeycomb filter is higher than the aperture ratio of the exhaust gas emission cells (11, 11A, 11B) of the honeycomb filter, the cross-sectional area of each exhaust gas emission cell (11, 11A, 11B) is larger than the cross-sectional area of each exhaust gas introduction cell (12, 12A), and among the sides forming the polygon (12a, 12b, 12c, 12d, 12e, 12f), the number of sides (12d, 12e) facing the exhaust gas introduction cells (12, 12A) across the cell partition walls (13, 13a, 13b) is larger than the number of sides (12a, 12b, 12c) facing the exhaust gas emission cells (11, 11A, 11B) across the cell partition walls (13, 13a, 13b), wherein, in a cross section perpendicular to the longitudinal direction of the cells, the exhaust gas introduction cells (12, 12A) are pentagonal with three 90° internal angles and two non-adjacent 135° internal angles and the exhaust gas emission cells (11, 11A, 11B) are square, and each exhaust gas emission cell is surrounded by eight exhaust gas introduction cells,_and wherein the exhaust gas introduction cells (12, 12A) each have the same shape, except for the exhaust gas introduction cells (12, 12A) that are adjacent to the outer wall. a honeycomb fired body including porous cell partition walls (13, 13a, 13b, 13c) defining a plurality of cells that serve as channels of exhaust gas, exhaust gas introduction cells (12, 12A) each having an open end at an exhaust gas inlet side and a plugged end at an exhaust gas outlet side, exhaust gas emission cells (11, 11A, 11B) each having an open end at the exhaust gas outlet side and a plugged end at the exhaust gas inlet side, and an outer wall on the periphery thereof, wherein the cross-sectional shape of each exhaust gas introduction cell (12, 12A) in a plane perpendicular to the longitudinal direction thereof is entirely uniform from the end at the exhaust gas inlet side to the end at the exhaust gas outlet side excluding the plugged portion, the cross-sectional shape of each exhaust gas emission cell (11, 11A, 11B) in a plane perpendicular to the longitudinal direction thereof is entirely uniform from the end at the exhaust gas inlet side to the end at the exhaust gas outlet side excluding the plugged portion, the cross-sectional shape of each exhaust gas introduction cell (12, 12A) in a plane perpendicular to the longitudinal direction thereof is a polygon, the exhaust gas emission cells (11, 11A, 11B), except for the cells adjacent to the outer wall, are each adjacently surrounded fully by the exhaust gas introduction cells (12, 12A) across the porous cell partition walls (13, 13a, 13b, 13c), the cells adjacent to the outer wall include the exhaust gas introduction cells (12, 12A) and the exhaust gas emission cells (11, 11A, 11B), the aperture ratio of the exhaust gas introduction cells (12, 12A) of the honeycomb filter is higher than the aperture ratio of the exhaust gas emission cells (11, 11A, 11B) of the honeycomb filter, the cross-sectional area of each exhaust gas emission cell (11, 11A, 11B) is larger than the cross-sectional area of each exhaust gas introduction cell (12, 12A), and among the sides forming the polygon (12a, 12b, 12c, 12d, 12e, 12f), the number of sides (12d, 12e) facing the exhaust gas introduction cells (12, 12A) across the cell partition walls (13, 13a, 13b) is larger than the number of sides (12a, 12b, 12c) facing the exhaust gas emission cells (11, 11A, 11B) across the cell partition walls (13, 13a, 13b), wherein, in a cross section perpendicular to the longitudinal direction of the cells, the exhaust gas introduction cells (12, 12A) are pentagonal with three 90° internal angles and two non-adjacent 135° internal angles and the exhaust gas emission cells (11, 11A, 11B) are square, and each exhaust gas emission cell is surrounded by eight exhaust gas introduction cells,_and wherein the exhaust gas introduction cells (12, 12A) each have the same shape, except for the exhaust gas introduction cells (12, 12A) that are adjacent to the outer wall.