A dust collecting apparatus for an electric precipitator, capable of adsorbing and filtering fine dust contained in air in an air ventilation apparatus such as an air conditioner or an air purifier and, more specifically, to a dust collecting apparatus for an electric precipitator which is capable of improving manufacturability and dust collection performance because the dust collecting apparatus comprises a first connection unit that is continuously provided on one side of a plurality of first dust collection plates, and is capable of improving assemblability because a first dust collection unit and a second dust collection unit can be assembled at accurate positions in a first case and a second case, respectively.