To reliably prevent a drop in the function of injectors resulting from a rise in the temperature of excess fuel in the injectors without having to add a new part.In a common rail fuel injection control system according to the present invention, when it is determined that an engine rotational speed Ne, a vehicle velocity V and a rail pressure exceed respective predetermined references, the count value of a determining counter is increased (steps S100 to S106), and when it is determined that the engine rotational speed Ne, the vehicle velocity V and the rail pressure do not exceed the respective predetermined references, the count value of the determining counter is decreased (steps S108 to S114), and next, when it is determined (step S116) that the count value of the determining counter exceeds a predetermined protection initiation reference Cs, limitation of the fuel injection amount and the rail pressure and correction of a smoke limit value are performed (see steps S120 to S124) until the count value of the determining counter falls below the predetermined protection initiation reference, whereby injector protection is performed.