NOVELTY - The system (11) has an output line (18) to connect a high pressure tank (2) and an external connection port (17). A filling side non-return valve (12) is provided in a filling line (19), to permit the flow of the high pressure gas which flows in the tank and to prevent a reverse flow. A solenoid valve (14) is provided in the output line. The output line is switched to a closed state by the excess flow valve, when the differential pressure of the inlet pressure at side of tank and the outlet pressure at side of external connection port is more than setting differential pressure.    USE - High-pressure-gas filling output system for vehicle such as compressed-natural gas motor vehicle, hydrogen gas motor vehicle and fuel-cell electric vehicle.    ADVANTAGE - The high pressure gas is flowed backward in the output line, when filling the tank through the high pressure gas at the filling line, thus the damage to the filter element by leaving of contamination from filter can be prevented, and the generation of the new contamination by damage to the filter element can be prevented. The outflow of the high pressure gas in the tank can be stopped reliably in the short time, and the amount of gas outflow to the exterior can be decreased. The loss by the outflow of the high pressure gas in the tank can be reduced, and the influence of high pressure gas with respect to ambient environment can be prevented. The excess flow valve can be integrated to the output side non-return valve, thus the miniaturization of the high pressure gas filling output system can be achieved. The channel between the excess flow valve and output side non-return valve can be shortened, thus the pressure loss of output line can be reduced. The responsiveness of the excess flow valve with respect to outflow flow volume can be improved by shortening the channel.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit diagram of the high-pressure-gas filling output system.    High pressure tank (2)    High-pressure-gas filling output system (11)    Filling side non-return valve (12)    Solenoid valve (14)    External connection port (17)    Output line (18)    Filling line (19)