Disclosed is a filtering device having a structure in which a charging portion and a dust collecting portion are improved. The disclosed filtering device comprises: a charging portion for charging fine dust, the charging portion including a case having one side, through which fine dust is introduced, a plurality of beam electrodes inserted into the case and spaced apart from each other along a depth direction of the case wherein a first voltage is applied thereto, and line electrodes arranged inside the case and spaced apart from the plurality of beam electrodes, respectively, so that a second voltage is applied thereto to generate a voltage difference with the beam electrodes; and a dust collecting portion for collecting the charged fine dust, the dust collecting portion including a first dust collecting electrode to which a first dust collecting voltage is applied, a second dust collecting electrode to which a second dust collecting voltage is applied to generate a voltage difference with the first dust collecting electrode, and a dielectric spacer which is disposed between the first dust collecting electrode and the second dust collecting electrode to space the first dust collecting electrode and the second dust collecting electrode apart from each other and serve as a dielectric.