A device for cleaning the drying air of a cellulose dryer (10). In the cellulose dryer a blower tower (12) or the like is arranged next to the actual drying section (20). The blowers (14) remove humid air from this drying section and direct heated air as drying air back to this drying section. At the suction side of the blowers in the blower tower there is arranged one or more heating devices (26), such as steam radiators, for reheating the removed humid air. A filter net (28, 34) is arranged in front of the heating device on the front side of the heating device, in order to filter the air being heated before it is heated. The device further comprises a cleaning device (50) for cleaning the filter net, and transport means (36, 38, 40, 42; 46), with which the filter net can be moved in parallel with the inlet plane of the heating device, and moved at least partly from the position in front of the inlet side of the heating device to the location of the cleaning device.