To provide a fuel supply device improving low temperature startability of an internal combustion engine.

This invented fuel supply device supplies fuel to the internal combustion engine and is provided with a fuel component separation means 14 distilling and separating low ignition point component or low boiling point component in fuel, and a fuel change over means 16 selectively changing fuel supplied to the internal combustion engine. Fuel of low ignition point component or low boiling point component is supplied at a time of low temperature start of the internal combustion engine. The fuel component separation means 14 is installed in an exhaust gas route of the internal combustion engine and is provided with a fuel vaporizer 42. And the fuel vaporizer consists of a fin part erectly provided on an outer circumference surface of an exhaust pipe 44 in the exhaust route and a shell body storing the fin part and formed concentrically with the exhaust pipe.