Abstract: A filter device capable of simultaneously effecting centrifugal separation and filtration comprises a hollow main body closed at one end thereof and adapted for effective use in a centrifuge, at least one filter medium disposed inside the hollow main body substantially along the axis thereof and adapted to partition the interior of the hollow main body into plural compartments, at least one of the compartments being a liquid feeding compartment and another compartment being a filtrate receiving compartment, wherein liquid entering the liquid feeding compartment is centrifuged and simultaneously filtered by the filter medium, and the filtrate flows into the filtrate receiving compartment. This filter device is used, for example, for the removal of proteins from blood.