Alcohol fuels have been considered for use as automotive fuel since two energy crises in the 1970's, but they have a defect of high latent heat of vaporization. Therefore, in order to improve vaporization of methanol, the authors have made the fuel vaporizing device with which to heat the mixture and eliminate the fuel film flow. This paper is a study on the characteristics of vaporization and engine performance acoording to the change of heating water temperature by means of the fuel vaporizing device. The study shows that as the vaporization of mixture improves, the mixture of methanol becomes homogenized and the fuel film flow decreases, which results in the increase of vaporization rate. And the increase of the vaporization rate improves the engine performance of the alcohol-fueled spark ignition engine.