A fuel cell system includes: a fuel cell including an anode, a cathode, and an electrolyte interposed between the anode and the cathode; and a purifying apparatus including a catalyst layer that purifies an effluent discharged from the anode. The purifying apparatus has a porous sheet including the catalyst layer and two flow paths disposed on both sides thereof. One of the flow paths has an inlet into which the effluent discharged from the anode is introduced, and the other flow path has an inlet into which air is introduced and an outlet. The effluent discharged from the anode is passed through the porous sheet for purification and then discharged from the outlet.