To surely trap bubbles on a surface of a filter, and also to surely remove bubbles stuck to the surface.

The filter 13 set in an ink feeding passage has a construction in which an insulating layer 53 whose surface has a low wettability is formed on a surface of an electrically-conductive substrate 52 where a plurality of through-holes 13a are formed. An electric potential of the electrically-conductive substrate 52 is made controllable by a driver IC. A diaphragm 40 where an ink supply port 12 brought into contact with ink in the ink feeding passage is formed is held at a ground potential. When recording is carried out in the inkjet recorder, the electric potential of the electrically-conductive substrate 52 is controlled to be the ground potential. When purging is carried out in the inkjet printer, the electric potential of the electrically-conductive substrate 52 is controlled to be a predetermined potential. The wettability of the surface of the insulating layer 53 is enhanced by the electro-wetting phenomenon.