A discharge device comprising: a low-potential counter electrode constituted by at least three flat-plate portions, a first connecting portion, and a second connecting portion which are integrally formed of one conductive plate body, the at least three flat-plate portions having elongated shapes and forming flat plates disposed almost parallel to each other, the first connecting portion serving to connect one-end portions of the elongated shapes of the at least three flat-plate portions, the second connecting portion serving to connect the other-end portions of the elongated shapes of the at least three flat-plate portions; a high-voltage-side discharge electrode which forms a wire, is arranged to extend among adjacent ones of the flat-plate portions in a lengthwise direction of the elongated shapes; a lower frame located below the counter electrode and the discharge electrode, made of an insulating material, and serving to support the counter electrode; a first upper frame made of an insulating material and serving to cover the first connecting portion of the counter electrode from above; and a second upper frame made of an insulating material and serving to cover the second connecting portion of the counter electrode from above, characterized in that the high-voltage-side discharge electrode has a potential higher than the potential of the counter electrode, wherein each of the first upper frame and the second upper frame has an insulating wall (505, 605) which is made of an insulating material, stands upward along the end portions of the at least three flat-plate portions, and has notches (506, 606) through which the discharge electrode extends, and wherein each of the first upper frame and the second upper frame has an extending portion (507, 607) which extends from a base of the insulating wall toward the lower frame, and together with the lower frame, isolates the first connecting portion and the second connecting portion from the discharge electrode. a low-potential counter electrode constituted by at least three flat-plate portions, a first connecting portion, and a second connecting portion which are integrally formed of one conductive plate body, the at least three flat-plate portions having elongated shapes and forming flat plates disposed almost parallel to each other, the first connecting portion serving to connect one-end portions of the elongated shapes of the at least three flat-plate portions, the second connecting portion serving to connect the other-end portions of the elongated shapes of the at least three flat-plate portions; a high-voltage-side discharge electrode which forms a wire, is arranged to extend among adjacent ones of the flat-plate portions in a lengthwise direction of the elongated shapes; a lower frame located below the counter electrode and the discharge electrode, made of an insulating material, and serving to support the counter electrode; a first upper frame made of an insulating material and serving to cover the first connecting portion of the counter electrode from above; and a second upper frame made of an insulating material and serving to cover the second connecting portion of the counter electrode from above,