A filter cartridge formed by winding, in a twill construction, a band-shaped
unwoven
cloth, which contains thermoplastic fibers and at least a part of its fiber intersections
are stuck thereon, so that a cylindrical shape can be obtained, wherein 1. two
types of filtrating layers are used, 2. unwoven cloth having opening hole parts
is used, 3. an end face seal part is provided on both end parts of the cartridge,
4. unwoven cloth having a tongue piece part is used, or 5. two or more pieced of
unwoven cloth are wound simultaneously, whereby those characteristic of the filter
cartridge such as liquid permeability, filterable life, and stability of filtration
accuracy can be kept in balance with each other.