To protect an oil seal interposed between a low pressure fuel gallery and a lubrication oil part in a fuel injection pump from a pulsation pressure of fuel.

This structure is formed that an accumulator or a throttle passage 322, serving as a means to reduce the generation of a pulsation pressure of fuel, is arranged in a passage to interconnect a low pressure fuel gallery 321 and an oil seal 306 for fuel seal. The throttle passage 322 consists of a different piece. Further, the throttle passage 322 is formed such that a gap is provided between the outer periphery of the rotor shaft 9a of a feed pump and the wall surface at the interior part for the rotor shaft of a pump housing.