A fuel supply apparatus reduces the fuel vaporization and leakage by means that the positions of vaporization and leakage and their amount in the fuel tank and the fuel pipe is detected properly in case of using a low boiling point fuel having a vapor phase in the normal temperatures and atmospheric pressures, and the fuel state is controlled based on those detected values. By providing another container made of elastomatic material having an expandable mechanical characteristic inside the fuel storing container, the low boiling point fuel is stored in the separate container. A flow rate controlling apparatus heats and cools the fuel pipe leading the low boiling point fuel stored in the fuel storing container to the engine. A flow rate controlling apparatus adjusts the flow rate of the fuel in the fuel pipe for leading the low boiling point fuel stored in the fuel storing container to the engine.