A fuel cell system comprises first and second fuel cell stacks in which directions of a positive electrode and a negative electrode of adjoining terminal electrodes are set to be opposite to one another. First and second conductive plates are incorporated at ends on an identical side of the first and second fuel cell stacks. First and second connecting plate sections are provided to extend from the first and second conductive plates closely to one another under the first and second fuel cell stacks. The first and second connecting plate sections are electrically connected by strand wires having flexibility. Accordingly, it is possible to reliably avoid any action of stress which would be otherwise caused by vibration or the like at a connecting portion for electrically connecting the first and second fuel cell stacks to one another which are arranged in parallel to one another.