Fuel cells offer the potential of ultra-low emissions combined with high efficiency. Hydrogen can be supplied to a fuel cell by reforming hydrocarbon fuels such as methanol or gasoline. Gasoline is more advantageous in infrastructure issues than pure hydrogen or methanol. The purpose of this study is to elucidate the basic characteristics of the gasoline reformer. Water and isooctane as a reference of gasoline separately evaporated were mixed at various excess water rations, and reformed by a platinum-ruthenium catalyst. This experiment was performed at the range of reformer temperatures from 700 to 850℃ in gasoline reforming. The components of CO, CO_2,H_2O, and H_2 were measured by a FT-IR analyzer and a gas chromatograph. The optimum operating conditions of the hybrid system were clarified from the result of the reforming experiment.