A fuel cell system includes a fuel cell stack that generates electricity by an electrochemical reaction using a fuel gas; an insulating first passage member through which produced water that is produced by the electrochemical reaction in the fuel cell stack and off-gas that is discharged from the fuel cell stack pass; a conductive second passage member that is connected to the first passage member; and a produced water flow disrupting portion that is provided on the first passage member and breaks up or stops the flow of the produced water that is introduced from an inside wall of the first passage member to the second passage member.