In an innercam system fuel injection pump, plungers 15 are provided in the direction of the radius of a rotating member 10 which rotates in synchronization with the engine. A cam ring 18, which regulates the movement of the plungers, is fixed in a housing 2. A first sleeve 25 for regulating the timing with which a cutoff port 22 opens and a second sleeve 26 for regulating the timing with which an intake port 21 opens are externally fitted on the rotating member 10 in such a manner that they can slide freely. The first sleeve 25 and the second sleeve 26 interlock with each other in a specific relationship and a timer mechanism 40, which is directly linked to the second sleeve 26, controls the quantity of rotation of the second sleeve 26. With this, stable injection timing control can be achieved.