To provide a filter medium improved in maintenance properties and capable of enhancing a filtering function without obstructing the flowability of a fluid.
The filter medium is so constituted that the fluid W is allowed to flow in from one of the inside and outside in the diametric direction of a coil spring-shaped filter medium main body 70 and allowed to flow out from the other side in the diametric direction of the filter medium. A plurality of fluid flowing grooves 9 traversing the filter medium main body 70 in the diametric direction are formed to the filter medium main body 70 over the total length of the filter medium main body 70 and the cross-sectional area of each of the upstream openings 9a of the fluid flowing grooves 9 is made larger than that of each of the downstream openings 9b of the filter medium main body 70.
SUGIMOTO TAKIO
Ken Takada
Kurose Yasuhisa
Yoshihito Shimizu
Toshiya Kido