PURPOSE: Provided is a fuel cell system, which improves energy utility efficiency and electric power generation performance, and reduces the fuel consumption. CONSTITUTION: The fuel cell system generates electric power by the electrochemical oxidation at an anode and the electrochemical reduction at a cathode, wherein a fuel recovery line(104) is connected to the anode and an air supply line(107) and air discharge line(108) are connected to the cathode. In the fuel system, a hydrogen gas separator(121) is disposed on the fuel recovery line(104); the hydrogen gas separator(121) and a burner(112a) of a moistener(112) are connected to a hydrogen gas recovery line(122) to reutilize the hydrogen separated by the hydrogen gas separator(121) as a fuel for the moistener(112); a water separator(123) is disposed on the air discharge line(108); and the water separator(123) and a water container(112b) of the moistener(112) are connected to a water recovery line(124) to supply the water separated by the water separator(123) to the water container(112b).
