A fuel cell system comprises: noise detection means for detecting the magnitude of noise in a driver's cabin of a fuel cell vehicle in which the fuel cell system is installed; and a control apparatus for controlling the operation of auxiliary machines. The control apparatus performs high-potential avoidance control to increase electric power consumed by the auxiliary machines so that a power-generation voltage of a fuel cell 1 becomes equal to or lower than a predetermined value, based on noise detected by the noise detection means.