A dust collecting apparatus comprising: a gas flow path through which a gas containing particulate matter can flow; a ground electrode provided along the gas flow path and having an aperture ratio that allows the gas to pass along a cross section of the flow path orthogonal to the gas flow; a dust-collecting filter layer arranged adjacent to the ground electrode and having an aperture ratio that allows the gas to pass along the cross section of the flow path orthogonal to the gas flow and an aperture ratio that allows the gas having flown into the dust-collecting filter layer to flow in the direction along the gas flow in the flow path; and a discharge electrode (3, 4) provided in the flow path, wherein the discharge electrode (3, 4) comprises discharge units formed in a thorn shape extending from a main part of the discharge electrode (3, 4) toward the ground electrode in a direction transverse to the flow path, with tips of the discharge units being away from the ground electrode by a predetermined interval, wherein the apparatus is arranged to apply a high voltage to generate an ion wind inducing and forming a secondary flow in a direction orthogonal to the gas flow from the discharge units of the discharge electrode (3, 4) to the ground electrode, between the discharge electrode (3, 4) and the ground electrode, thereby generating a helical gas flow between the gas flow path and the dust-collecting filter layer, characterized in that a distance S between nodes of a perpendicular brought down from the tips of adjacent discharge units of the discharge electrode to the opposite ground electrode measured along the ground electrode and a distance D between the tips of the discharge units of the discharge electrode and the ground electrode fulfill the criterion that S is from 0.8D to 3 D inclusive, wherein the ground electrode has an aperture ratio of from 65% to 85%. a gas flow path through which a gas containing particulate matter can flow; a ground electrode provided along the gas flow path and having an aperture ratio that allows the gas to pass along a cross section of the flow path orthogonal to the gas flow; a dust-collecting filter layer arranged adjacent to the ground electrode and having an aperture ratio that allows the gas to pass along the cross section of the flow path orthogonal to the gas flow and an aperture ratio that allows the gas having flown into the dust-collecting filter layer to flow in the direction along the gas flow in the flow path; and a discharge electrode (3, 4) provided in the flow path, wherein the discharge electrode (3, 4) comprises discharge units formed in a thorn shape extending from a main part of the discharge electrode (3, 4) toward the ground electrode in a direction transverse to the flow path, with tips of the discharge units being away from the ground electrode by a predetermined interval, wherein the apparatus is arranged to apply a high voltage to generate an ion wind inducing and forming a secondary flow in a direction orthogonal to the gas flow from the discharge units of the discharge electrode (3, 4) to the ground electrode, between the discharge electrode (3, 4) and the ground electrode, thereby generating a helical gas flow between the gas flow path and the dust-collecting filter layer, characterized in that a distance S between nodes of a perpendicular brought down from the tips of adjacent discharge units of the discharge electrode to the opposite ground electrode measured along the ground electrode and a distance D between the tips of the discharge units of the discharge electrode and the ground electrode fulfill the criterion that S is from 0.8D to 3 D inclusive, wherein the ground electrode has an aperture ratio of from 65% to 85%.