To provide a fuel injection pump suppressing a timer delay angle in a low load area, improving the timer delay angle in a middle load area, and having a simple structure.

The fuel injection pump equipped with a load timer mechanism LST correcting injection timing according to an engine load is provided with a first annular groove 55 at an axial position differing from an opening 57c of a fuel releasing passage portion 57 on an outer peripheral surface of a governor shaft 39, and a second annular groove 53 at an axial position differing from an opening 51a of a port portion 51 on an inner peripheral surface of a governor sleeve 33. In a middle load state, both annular grooves 55, 53 are superimposed with each other, a fuel collecting portion 56 at least divided by both superimposed annular grooves 55, 53 is communicated to the port portion 51, thereby communicating the port portion 51 and the fuel releasing passage portion 57. In a low load state, the first and second annular grooves 55, 53 are slightly superimposed or not superimposed with each other, so that the port portion 51 and the fuel releasing passage portion 57 are interrupted.