The device has a base and a water tank, an electrode tank, a moisture separator and a pumping pump inside the base. The water tank is provided with a plurality of radiating pipes. The electrode tank is connected with the water tank and the hydrogen gas generated by the electrode tank can flow into the water tank. The moisture separator is respectively provided with an air-intake pipe and an air-supply pipe connected to the water tank and extended to the outer part of the base so that hydrogen gas in the tank can be output. In addition, pumping pump can take the liquid from the water tank to the electrode tank. In this way, the hydrogen gas can be led to the external engine and mixed with the fuel to increase the combustion rate of the fuel in the engine