A fuel injection apparatus for an internal combustion engine, including: a fuel injection valve that injects fuel into a cylinder of the internal combustion engine and is arranged such that the injected fuel is headed in a direction that crosses a central axis of the cylinder; and a fuel pressure control unit (23, 24) that controls a pressure of the fuel that is supplied to the fuel injection valve, wherein: the fuel injection valve has an upper nozzle hole group that includes a plurality of nozzle holes and is located on an upper side in a direction of the central axis, and a lower nozzle hole group that includes a plurality of nozzle holes and is located on a lower side in the direction of the central axis; and the fuel injection valve is configured such that a fuel density downstream of the lower nozzle hole group in an injection direction is higher than a fuel density downstream of the upper nozzle hole group in an injection direction, characterized in that: the fuel injection valve is configured such that a specific fuel pressure value, at which a rate of change in a downward injection angle with respect to a reference line that is perpendicular to the central axis and passes through a distal end of the fuel injection valve changes, is within a variation range of the fuel pressure; and the fuel pressure control unit (23. 24) controls the pressure of the fuel that is supplied to the fuel injection valve so that the pressure becomes lower than the specific fuel pressure value when the internal combustion engine is operating at a low rotational speed lower than a predetermined rotational speed, and to be equal to or higher than the specific fuel pressure value when the internal combustion engine is operating at a high rotational speed higher than or equal to the predetermined rotational speed. a fuel injection valve that injects fuel into a cylinder of the internal combustion engine and is arranged such that the injected fuel is headed in a direction that crosses a central axis of the cylinder; and a fuel pressure control unit (23, 24) that controls a pressure of the fuel that is supplied to the fuel injection valve, wherein: the fuel injection valve has an upper nozzle hole group that includes a plurality of nozzle holes and is located on an upper side in a direction of the central axis, and a lower nozzle hole group that includes a plurality of nozzle holes and is located on a lower side in the direction of the central axis; and the fuel injection valve is configured such that a fuel density downstream of the lower nozzle hole group in an injection direction is higher than a fuel density downstream of the upper nozzle hole group in an injection direction, characterized in that: the fuel injection valve has an upper nozzle hole group that includes a plurality of nozzle holes and is located on an upper side in a direction of the central axis, and a lower nozzle hole group that includes a plurality of nozzle holes and is located on a lower side in the direction of the central axis; and the fuel injection valve is configured such that a fuel density downstream of the lower nozzle hole group in an injection direction is higher than a fuel density downstream of the upper nozzle hole group in an injection direction, characterized in that: the fuel injection valve is configured such that a specific fuel pressure value, at which a rate of change in a downward injection angle with respect to a reference line that is perpendicular to the central axis and passes through a distal end of the fuel injection valve changes, is within a variation range of the fuel pressure; and the fuel pressure control unit (23. 24) controls the pressure of the fuel that is supplied to the fuel injection valve so that the pressure becomes lower than the specific fuel pressure value when the internal combustion engine is operating at a low rotational speed lower than a predetermined rotational speed, and to be equal to or higher than the specific fuel pressure value when the internal combustion engine is operating at a high rotational speed higher than or equal to the predetermined rotational speed.