Fluid filter

A fluid filter provided with a case body and a filter medium;

• the case body having an inlet and an outlet for a fluid at necessary positions respectively and containing a holder defined therein to communicate with the inlet and the outlet;
• the filter medium being made of a porous material having an appropriate flexibility and a uniform density when not compressed and being removably housed in the holder so as to allow the fluid introduced through the inlet in the holder to pass through the filter medium where fine extraneous substances contained in the fluid are captured and to discharge the thus cleaned fluid through the outlet;
• wherein the case body comprises a plurality of pressing portions formed on an internal surface of the case body, the plurality of pressing portions for compressing the filter medium housed in the holder;
• the plurality of pressing portions being pressed against the filter medium housed in the holder to compress it and form a plurality of compressed regions having an increased rate of capturing extraneous substances, enabling the filter medium to capture the extraneous substances throughout the filter medium even if the extraneous substances differ in size and wherein said plurality of pressing portions comprise a plurality of ribs formed in the case body.