PURPOSE: To prevent oil leakage on the periphery of a rotor in a fuel injection pump by separating a geverner chamber from a pump chamber provided with a rotor by plates with seal materials.

CONSTITUTION: A feed pump 16 rotated by a drive shaft 14 pressurizes fuel, and introduces into a pump chamber 5 via a governer chamber 9, a pressurizing chamber 26, a control valve 10, and a groove 13 of a bush 11. In the pump chamber 5, a plunger 4 is provided to be reciprocated by the rotation of a rotor 6. The rotor 6 is shaped into a cylinder, and provided with the governer chamber 9 on the periphery of its one end. On both sides of the pump chamber 5, plates 18 and 19 are provided to be in touch with the periphery of the rotor 6 on their one ends, while seal materials 50 and 51 are applied to the upper and lower sides of the plate 18 on the side of the governer chamber 9 for preventing the pump chamber 5 from leakage of fuel.