NOVELTY - A water treating unit consists of a fuel cell portion (4), a recycled water processing mechanism (5), water tank portions, a water treatment portion (7) and a deaeration portion(8). The fuel cell portion carries out reaction of hydrogen of anode (1) side and oxygen of cathode (2) side through an electrolyte. The water tank portion (A) (6a) contains recycled water with high carbon dioxide concentration which is collected by recycled water processing mechanism. The water tank (B) (6b) provided with recycled water with low concentration of carbon dioxide.    USE - For recovering and processing moisture content of process gas in fuel cell system used for electric power generation.    ADVANTAGE - The water treating unit is economical, and effectively reduces carbon dioxide concentration in recycled water.    DETAILED DESCRIPTION - A water treating unit consists of a fuel cell portion, a recycled water processing mechanism, water tank portions, a water treatment portion and a deaeration portion. The fuel cell portion carries out reaction of hydrogen of anode side and oxygen of cathode side through an electrolyte. The recycled water processing mechanism which carries out processing the recycled water collected from the predetermined process gas. The water tank portion (A) contains recycled water with high carbon dioxide concentration which is collected by recycled water processing mechanism. The deaeration mechanism carries out deaerating carbon dioxide of recycled water. The water tank (B) provided with recycled water with low concentration of carbon dioxide. The water treatment portion processes recycled water. The water treatment portion processes the mixed water from water tank (B).    DESCRIPTION OF DRAWING(S) - The figure shows a schematic block diagram of fuel cell power generating device. (Drawing includes non-English language text)    Anode (1)    Cathode (2)    Electrolyte (3)    Fuel cell portion (4)    Recyclced water processing mechanism (5)    Water tank portion (A) (6a)    Water tank portion (B) (6b)    Water treatment portion (7)    Deaeration mechanism (8)