A fluid filter is provided with a case body defining therein a holder and having
pressing portions formed on the internal wall surface of the case body. The pressing
portions can compress a filter medium housed in the holder. The pressing portions
are pressed against the filter medium housed in the holder to compress it and form
a compressed region at a desired position of the filter medium, where the rate
of capturing extraneous substances is increased. Thus, even if various sizes of
the extraneous substances are contained in a fluid introduced through the inlet
into the holder, the filter medium can capture the extraneous substances in its
entirety. The degree of compression of the compressed region in the filter medium
changes depending on the height of each pressing portion.
