A granulator device (1) for the treatment of powdered material, in particular pharmaceutical powdered material, comprises a substantially cylindrical container (2), in which there is a chamber (4) for treatment of the powdered material using a fluid flow fed into the chamber (4); filtering means (5) for filtering the inside of the chamber (4), the filtering means (5) being located in the chamber (4) and comprising at least one filter (5) with a cylindrical metal mesh filtering wall (6); and means (P) for cleaning the filtering means (5) which can be activated during maintenance operations, the cleaning means comprising at least one element (7) rotating about each filter (5) and supporting diffuser means (8) designed to diffuse a service fluid on the cylindrical wall (6) in order to eliminate any impurities trapped in the filter (5) wall (6); the cleaning means (P) also comprise means (9) for temporarily opening at least one portion (10) of the filter (5) to allow the service fluid to flow out of the filter (5) together with the impurities.