Abstract: A fuel cell system includes a fuel cell which generates electric energy by an electro-chemical reaction, a water tank which stores water from the fuel cell, an intake pipe which has an inlet port for introducing moisture-containing exhaust gas from the fuel cell into the water tank and is connected with the water tank, an exhaust pipe which has an exhaust port for exhausting gas from the water tank and is connected with the water tank, and a partition member which is provided in the water tank at a position lower than the inlet port for partitioning an interior of the water tank into an upper space and the lower space. The fuel cell system is capable of collecting water from the fuel cell easily and efficiently without depending upon a large component or decreasing power generation efficiency.