Abstract: An electrostatic filter type gas cleaner having relatively electrically insulated discharge and collecting electrodes between which the gas to be cleaned is passed. The collecting electrodes are mounted concentrically around the discharge electrodes and are rotatable relative to them so that particles separating from the gas and depositing on the collecting electrodes are almost immediately thrown away from these electrodes. A casing surrounds the collecting electrodes and serves to collect and carry away the particles separated from the gas. The interior space of the casing is not influenced by the gas flow between the discharge and collecting electrodes. Moreover, means are provided at the peripheral part of a prolongation, extending in the direction of the gas stream, of the annular gap between the discharge and collecting electrodes to lead off the peripheral portion of the gas stream radially outwards to a separate outlet.