Abstract: The flush-back filter according to the invention uses as supporting element for at least one filter element a support cage which is arranged firmly on the inside of the filter housing and is penetrated from the interior to the exterior by the medium to be filtered. At the interior of the support cage a lifting or rotating flush-back device is located which upon its movement passes over the slot-type windows of the support cage in succession. The slot-type windows are arranged on the support cage in several groups in such a way that the windows of the one group are offset against those of the other group(s) in the direction of movement of the flush-back device, in such a way that the windows of the one group lie at least with the webs of another group on a common plane. In this way the entire filter area is subjected to the flush-back operation during this operation only over very small surface areas, with the result that small flush-back volumes can be used and the pressure drop is slight.