A fuel injection characteristic detection apparatus for a fuel feed system configured to inject fuel into one of a cylinder, an intake passage, and an exhaust passage of an internal combustion engine by using a fuel injection valve , the fuel injection characteristic detection apparatus comprising: fuel pressure obtaining means (S32) for successively obtaining pressure of fuel supplied to the fuel injection valve ; and pulsation pattern storing means (S35) for associating a pulsation pattern of fuel pressure, which defines the transition of the fuel pressure accompanying fuel injection of the fuel injection valve , with at least a fuel injection mode and a fuel pressure level at a present time point and for storing the associated pulsation pattern in a storage medium during a learning processing, wherein the injection mode is one of a number of injection stages, an injection quantity in each injection, an injection timing of each injection, characterized by pulsation pattern extraction means (S44) for extracting a pulsation pattern, which is related to only a fuel injection of nth-stage or after, from a pulsation pattern, which is related to a multi-stage injection and is obtained in a period where the multi-stage injection is performed, the fuel pressure at the time is successively detected and temporarily stored in a RAM, based on the pulsation pattern in the storage medium, wherein the multi-stage injection is performed in one burning cycle in a predetermined cylinder of the internal combustion engine, and the fuel injection of nth-stage or after is equivalent to a predetermined-stage injection, which is second-stage injection or after in the multi-stage injection, and compensation means (S12, S45) for correcting a command signal, which is for the fuel injection valve , based on the pulsation pattern, which is related to only the fuel injection of nth-stage or after and being extracted by the pulsation pattern extraction means (S44). fuel pressure obtaining means (S32) for successively obtaining pressure of fuel supplied to the fuel injection valve ; and pulsation pattern storing means (S35) for associating a pulsation pattern of fuel pressure, which defines the transition of the fuel pressure accompanying fuel injection of the fuel injection valve , with at least a fuel injection mode and a fuel pressure level at a present time point and for storing the associated pulsation pattern in a storage medium during a learning processing, wherein the injection mode is one of a number of injection stages, an injection quantity in each injection, an injection timing of each injection, characterized by pulsation pattern extraction means (S44) for extracting a pulsation pattern, which is related to only a fuel injection of nth-stage or after, from a pulsation pattern, which is related to a multi-stage injection and is obtained in a period where the multi-stage injection is performed, the fuel pressure at the time is successively detected and temporarily stored in a RAM, based on the pulsation pattern in the storage medium, wherein the multi-stage injection is performed in one burning cycle in a predetermined cylinder of the internal combustion engine, and the fuel injection of nth-stage or after is equivalent to a predetermined-stage injection, which is second-stage injection or after in the multi-stage injection, and compensation means (S12, S45) for correcting a command signal, which is for the fuel injection valve , based on the pulsation pattern, which is related to only the fuel injection of nth-stage or after and being extracted by the pulsation pattern extraction means (S44). <EOS>