To provide a filter device of fuel pump which can be applied to an existing manufacturing process easily, and has an excellent silencing effect.

To the tubular base 5 made of a soft resin, of a filter device having fuel passage 51 to feed fuel after filtering to the suction port 2 of a fuel pump 1, a sealed air chamber 57 surrounded by a soft resin wall 50, and opposing to the suction port 2 of the fuel pump 1 by sandwiching the fuel passage 51, is formed. By composing the filter device in such a way, an impeller pulsation sound can be reduced.