To improve the ignitability of fuel during the startup of an internal combustion engine by supplying the fuel heated by a fuel heating device into a combustion chamber during the startup of the internal combustion engine.

This fuel supply device 1 for an internal combustion engine E includes the fuel heating device 14 having a heat case 15 which forms a heating chamber 18 in a fuel supply passage 5 and a heater 16 for heating the fuel in the heating chamber 18 and a fuel injection valve 4 which is installed so as to face the intake passage 10 of the internal combustion engine E and injects the fuel supplied from the fuel heating device 14 into the combustion chamber 11 of the internal combustion engine E. An ECU 20 drives the heater 16 according to a first start signal generated by the startup operation performed by an operator and drives the fuel injection valve 4 in a preliminary injection mode for jetting the fuel for a preliminary injection time Ti in which the fuel does not reach the combustion chamber 11.