A filter device for fluids includes a housing (1) accommodating a filter element (5). The housing has an inlet (47) for the supply of fluid to be purified to a non-filtrate chamber (49) of the housing (1) and has an outlet 42 for the filtrate. The non-filtrate chamber is separated from a filtrate chamber (46) of the housing (1) by the filter medium (33). A magnetic field-generator unit (57) is arranged inside the non-filtrate chamber (49). An adhering surface a sleeve or casing (51) attracts ferromagnetic particles by a magnetic force effect. In the non-filtrate chamber (49), the sleeve (51) extends outside of the respective filter element (5) parallel to the inlet (47) and transversely to the outlet (42). The non-filtrate chamber (49) at least partially encompasses the outlet (42) at the point of transition to the filtrate chamber (46).