A filter assembly includes: a cylindrical diesel particulate filter disposed on a flow passage through which an exhaust gas from an engine is discharged, the filter having gas flow passages formed and disposed therein by dividing an inner space into a lattice form; and an electrode unit disposed at at least one of both side surfaces of the filter, the electrode unit receiving electric power to heat the filter. A plurality of regions resulting from division into a lattice form in the filter have alternately disposed open and closed sections. A device for reducing an exhaust gas including the above filter assembly is also provided.