Fuel supply apparatus for internal combustion engine

An ECU calculates the difference between the fuel pressure in a high-pressure distribution pipe and a target pressure when fuel is injected only from an air-intake passage injector. The ECU determines the bulk modulus of fuel that is associated with the coolant temperature. The ECU determines the amount of fuel that is to be discharged from a high-pressure pump based on the pressure difference and the bulk modulus. Then, the ECU actuates the high-pressure pump in accordance with the determined discharge amount.