A pressure accumulation type fuel injection system for accumulating high-pressure fuel, which is pressurized and pressure-fed by a fuel supply pump driven by an engine, in a common rail and for injecting the high-pressure fuel accumulated in the common rail into a cylinder of the engine through an injector, the pressure accumulation type fuel injection system including a pressure safety valve that opens when the fuel pressure in the common rail exceeds a limit set pressure in order to limit the fuel pressure in the common rail to the limit set pressure or under, comprising: fuel pressure sensing means for sensing the fuel pressure in the common rail; and an engine control unit for controlling the engine to avoid further continuation of an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds at least one of a pump usage allowable area, the fuel pressure in the common rail above which adversely affects reliability of the fuel supply pump, and an injector usage allowable area, the fuel pressure in the common rail above which adversely affects reliability of the injector, when the abnormally high-pressure state continues for a predetermined period; wherein the engine control unit includes abnormality diagnosing means for detecting an abnormality failure of the fuel supply pump when an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds a first determination value corresponding to the pump usage allowable area or a second determination value that is higher than the first determination value and affects performance degradation of the fuel supply pump, continues for a predetermined period; and the engine control unit stops an operation of the engine when a predetermined period passes after the abnormality failure of the fuel supply pump is detected by the abnormality diagnosing means, characterized in that the engine control unit includes rotation speed sensing means for sensing engine rotation speed; and the engine control unit stops the operation of the engine immediately when an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds the first determination value or the second determination value and the engine rotation speed sensed by the rotation speed sensing means exceeds a determination value, continues for a predetermined period. fuel pressure sensing means for sensing the fuel pressure in the common rail; and an engine control unit for controlling the engine to avoid further continuation of an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds at least one of a pump usage allowable area, the fuel pressure in the common rail above which adversely affects reliability of the fuel supply pump, and an injector usage allowable area, the fuel pressure in the common rail above which adversely affects reliability of the injector, when the abnormally high-pressure state continues for a predetermined period; wherein the engine control unit includes abnormality diagnosing means for detecting an abnormality failure of the fuel supply pump when an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds a first determination value corresponding to the pump usage allowable area or a second determination value that is higher than the first determination value and affects performance degradation of the fuel supply pump, continues for a predetermined period; and the engine control unit stops an operation of the engine when a predetermined period passes after the abnormality failure of the fuel supply pump is detected by the abnormality diagnosing means, characterized in that the engine control unit includes rotation speed sensing means for sensing engine rotation speed; and the engine control unit stops the operation of the engine immediately when an abnormally high-pressure state, in which the fuel pressure in the common rail sensed by the fuel pressure sensing means exceeds the first determination value or the second determination value and the engine rotation speed sensed by the rotation speed sensing means exceeds a determination value, continues for a predetermined period.