filter members 11 12 and the porous member 14 may be initially formed into a three layer integral sheet which is then cut into a suitable shape with its periphery welded by a thermal welding means such as ultrasonic welding or electrodeposition the coupling member 13 consists of an upper member 13 a having a flange 13 b and a lower member 13 c having a flange 13 d the upper and lower members 13 a 13 c are inserted from the upper side and the lower side of the filter 10 into the bore 14 a of the porous member 14 through the openings 11 b 12 b of the upper filer member 11 and the lower filter member 12 respectively then the upper and lower members 13 a 13 c are integrated together with their end faces secured to each other with an adhesive or the like a plurality of semicircular openings that provide fuel passages are formed in portions of the upper member 13 a and the lower member 13 c adjacent to their end faces so that a plurality of fuel inlets 13 e are formed when the end faces of the upper and lower members 13 a 13 b abut on each other the flanges 13 b 13.