A hydrogen-fueled internal combustion engine that uses liquid hydrocarbon fuel and hydrogen gas as fuel, which improves mixability of liquid hydrocarbon fuel and hydrogen gas and reduces the number of parts required for a fuel supply that supplies the two types of fuel. The hydrogen-fueled internal combustion engine includes a fuel injection device injecting hydrocarbon fuel; a fuel supply supplying hydrocarbon fuel to the fuel injection device; and a microbubble generation device generating microbubbles of hydrogen gas and mixing the generated microbubbles of hydrogen gas into liquid hydrocarbon fuel in the fuel supply. The hydrogen gas microbubbles are supplied, for instance, to a fuel supply path and fuel tank, which constitute the fuel supply.