Silencer for reducing acoustic noise of fuel cell system

A silencer for installation in a fuel cell system includes a plurality of expansion chambers adapted to connect to a predetermined apparatus of the fuel cell system, wherein the plurality of expansion chambers are adapted to serially reduce acoustic noise of air discharged from the predetermined apparatus in a first frequency band and a resonator connected to an expansion chamber of the plurality of expansion chambers, wherein the resonator is adapted to reduce acoustic noise received from the expansion chamber in a second frequency band which is different from the first frequency band, where one of the plurality of expansion chambers comprises an inlet pipe adapted to receive air from the predetermined apparatus, another of the plurality of expansion chambers comprises an outlet pipe adapted to discharge air flowed into the plurality of expansion chambers, and an intermediate pipe is disposed between the plurality of expansion chambers.