A Plasma or serum separation membrane that enables omitting centrifugal separation, is free from hemolysis attributed to destruction of red blood cells and realizes easy and rapid separation of plasma or serum from blood; and a filter apparatus including the plasma or serum separation membrane. In particular, a plasma or serum separation membrane being a membrane for separation of plasma or serum from blood and having a void ratio of 30% or below; and a filter apparatus comprising a filter member capable of attaining movement of plasma swifter than movement of blood cells and a plasma or serum separation membrane connected in series with a rear side of the filter member.