Abstract: An electric dust precipitator comprising a chamber; a pair of groups of dust collecting electrodes disposed in the chamber; a plurality of discharging wires disposed between the dust-collecting electrode groups, a high d.c. voltage being applied to the wires and electrodes; and two horizontal scraping means each of which includes two sliding bars, adapted to slide along opposite surfaces of the electrodes and having brackets at the inside thereof, and drawing plates, wherein ends of the drawing plates in pairs are pivotally mounted on the brackets and the other ends of the drawing plates in pairs are commonly suspended by chains, respectively, whereby the dust precipitated on the electrodes can be easily and completely removed by winding up the chains and hence moving up the scraping means.