To obtain net-like contact filter media with which allow the effective execution of a biochemical treatment in spite of slight water flow and convection and efficient purification by braiding piles on the outer peripheral surfaces of core bodies formed by braiding plural pieces of core wires having rigidity to form adhered pile net yarn and subjecting this net yarn to knotless knitting to required mesh openings.

The core wires 1B having rigidity are used as the cores 1A at the time of forming the adhered pile net yarn 1 and many pieces of the adhered piles 1D are extended and formed while the flexible wires 1C are braided at a suitable length toward the outer side where the adhered piles 1D are formed at the time of forming the cores 1A. The examples of the stock of the wires 1C for forming the adhered piles 1D include synthetic fiber stock, such as polyamide. Such adhered pile net yarn is used and is subjected to the knotless knitting to the required mesh openings, by which the net-like contact filter media 2 are constituted. At this time, the adhered pile net yarn having the length of the adhered piles corresponding to 3 to 10% of the mesh openings with respect to the mesh openings to be subjected to the knotless knitting is recommended to be used.