NOVELTY - A cooling apparatus for a fuel cell, comprises cooling piping (2) through which a cooling medium for cooling the fuel cell flows; a conductivity measuring unit (5) measuring a conductivity of the cooling medium that flows through the cooling piping; a conductivity reducing agent supply unit (6) supplying the cooling piping with a conductivity reducing agent for reducing the conductivity of the cooling medium; and a control unit (7) controlling the conductivity reducing agent supply unit in accordance with a value of the measured conductivity.    USE - As a cooling apparatus for a fuel cell mounted on a mobile object such as fuel cell vehicle.    ADVANTAGE - The cooling apparatus enables a decrease in the conductivity of the cooling medium flowing through the cooling piping and enables the conductivity of the cooling medium to be restrained from rising. The cooling apparatus enables the decrease in the conductivity of the cooling medium flowing through the cooling piping and enables the conductivity of the cooling medium to be restrained from rising. The large molecules residing on the protruded portion provided on the inner wall surface of the cooling system piping are discharged outside the cooling system piping by opening the discharge valve. Hence, the overflow of the large molecules disabled from residing on the protruded portion provided on the inner wall surface of the cooling system piping can be restrained. As a result, it is feasible to restrain decoupling between the ions and the higher alcohols due to the flow of the large molecules via the cooling system piping, and by extension the conductivity of the cooling water can be restrained from rising.    DETAILED DESCRIPTION - A cooling apparatus for a fuel cell, comprises cooling piping (2) through which a cooling medium for cooling the fuel cell flows; a conductivity measuring unit (5) measuring a conductivity of the cooling medium that flows through the cooling piping; a conductivity reducing agent supply unit (6) supplying the cooling piping with a conductivity reducing agent for reducing the conductivity of the cooling medium; and a control unit (7) controlling the conductivity reducing agent supply unit in accordance with a value of the measured conductivity. The control unit, when the value of the measured conductivity is equal to or larger than a predetermined value, controls the conductivity reducing agent supply unit to supply the cooling piping with the conductivity reducing agent. The conductivity reducing agent has a hydroxy group. The cooling piping has a protruded portion inwardly. The cooling apparatus further comprises a discharge valve for discharging the cooling medium flowing via the cooling piping. The control unit, after controlling the conductivity reducing agent supply unit to supply the cooling piping with the conductivity reducing agent, controls the discharge valve to discharge the cooling medium flowing via the cooling piping if a predetermined period of time elapses.    DESCRIPTION OF DRAWING(S) - The figure shows is schematic view of a cooling system.    Fuel cell stack (1)    Cooling piping (2)    Conductivity measuring unit (5)    Conductivity reducing agent supply unit (6)    Control unit (7)