Abstract: A fuel injection pump equipped with a rotary deflector, with which lifetime of the deflector is increased and maintenance cost which is required to replace the deflector when it is wasted due to cavitation erosion is decreased. The deflector comprises a stationary holder and a tip member which is supported rotatably by the stationary holder so that the tip member is rotated by fuel flow that outbursts from the plunger room through the inlet/spill port and impinges against the tip member when fuel injection ends, thereby evading concentrated impingement at a specific portion of the tip member and preventing occurrence of cavitation erosion.