A controller for an engine fuel control system, the controller comprising: a fuel injection quantity calculating section configured to calculate a fuel injection quantity based on at least one operating condition of an engine equipped with a high pressure fuel pump to supply high pressure fuel to at least one fuel injection valve (31A to 31D) that opens at a prescribed fuel injection timing to deliver the high-pressure fuel from the high pressure fuel pump to the engine; a fuel pressure estimate value calculating section configured to execute a calculation at a prescribed calculation time occurring before the prescribed fuel injection timing of a cylinder that occurs during a rising stroke of a pump plunger with the calculation estimating an estimated fuel pressure value of the high pressure fuel that will be acting on the fuel injection valve (31 A to 31D); a fuel injection quantity correcting section configured to correct the fuel injection quantity that was previously calculated to a corrected fuel injection quantity based on the estimated fuel pressure value that will exist at the fuel injection timing; and a fuel injection valve operating section configured to open the fuel injection valve (31A to 31D) at the prescribed fuel injection timing to discharge a quantity of fuel equal to the corrected fuel injection quantity; wherein the fuel pressure estimate value calculating section is further configured to set the prescribed calculation time for the calculating of the estimated fuel pressure value to occur before the prescribed fuel injection timing that occurs during the rising stroke of the pump plunger that drives the high pressure fuel pump to discharge the high-pressure fuel during the rising stroke of the pump plunger and to maintain a prescribed fuel pressure during a falling stroke of the pump plunger, wherein the fuel pressure estimate value calculating section is further configured to obtain the estimated fuel pressure value that will exist at the prescribed fuel injection timing by adding an actual fuel pressure acting on the fuel injection valve (31 A to 31D) at the prescribed calculation time to a compensation value based on an estimated amount by which the fuel pressure will increase during a period from the prescribed calculation time until the prescribed fuel injection timing, and wherein the compensation value is based on a common rail fuel pressure increase amount base value (ΔP0) calculated according to: ΔP 0 = K × y 1 − y 0 × Apump / Vcom + V 0 pump − y 0 × Apump, wherein K is a bulk modulus, Apump is the cross sectional area of the pump plunger, V0pump is the maximum volume of the compression chamber of the plunger pump, Vcom is the volume of the common rail, y1 and y0 are respectively the plunger lift amount of the plunger at the prescribed fuel injection time and at the prescribed calculation time. a fuel injection quantity calculating section configured to calculate a fuel injection quantity based on at least one operating condition of an engine equipped with a high pressure fuel pump to supply high pressure fuel to at least one fuel injection valve (31A to 31D) that opens at a prescribed fuel injection timing to deliver the high-pressure fuel from the high pressure fuel pump to the engine; a fuel pressure estimate value calculating section configured to execute a calculation at a prescribed calculation time occurring before the prescribed fuel injection timing of a cylinder that occurs during a rising stroke of a pump plunger with the calculation estimating an estimated fuel pressure value of the high pressure fuel that will be acting on the fuel injection valve (31 A to 31D); a fuel injection quantity correcting section configured to correct the fuel injection quantity that was previously calculated to a corrected fuel injection quantity based on the estimated fuel pressure value that will exist at the fuel injection timing; and a fuel injection valve operating section configured to open the fuel injection valve (31A to 31D) at the prescribed fuel injection timing to discharge a quantity of fuel equal to the corrected fuel injection quantity;