Disclosed is a fluid purifying apparatus (1) which is composed of a filter housing (2) having a fluid inlet opening (231) and a fluid outlet opening (221), and a filter member (3) contained in the filter housing (2) in such a manner that the filter member crosses the flow path of a fluid from the fluid inlet opening (231) to the fluid outlet opening (221). The fluid purifying apparatus (1) is characterized in that the bore diameter a of the fluid outlet opening and the shortest distance b between the filter member and the position of the inner peripheral portion of the fluid outlet opening farthest from the filter member satisfy the following relation: b ‰¥ a.
