The invention discloses an electrostatic dust collecting device which comprises a body, wherein an air inlet is formed in the front end of the body, and an air outlet is formed in the back end of thebody; an electrostatic dust collecting mechanism is arranged in the body and comprises an anode dust collecting barrel rotatably arranged in the body and a cathode discharge body fixedly arranged in the body; the cathode discharge body is arranged in the anode dust collecting barrel; a plurality of gaps extending along the length direction of the anode dust collecting barrel are formed in the wallof the anode dust collecting barrel, and the gaps are distributed around the anode dust collecting barrel; an ash removal mechanism is also arranged in the anode dust collecting barrel, the lower endof the ash removal mechanism is in contact with the inner wall of the anode dust collecting barrel and the lower end of the ash removal mechanism can move relative to the inner wall of the anode dustcollecting barrel. The device can remove dust in the electrostatic dust collecting mechanism effectively, so that the electrostatic dust collecting effect is improved, and meanwhile, dust which is removed is prevented from being elevated in the electrostatic dust collecting mechanism.