PURPOSE: To prevent deformation of an outer peripheral part of a distribution rotor by a method wherein a screw hole and a circular recess for surrounding the hole are formed on an end of the distribution rotor while a male screw of a vane feed pump is screwed into the screw hole with end faces contacting with each other inside the recess of the distribution rotor.

CONSTITUTION: A distribution rotor 14 is integrally formed with a rotating shaft 12 synchronizing with rotation of an engine, and the rotor 14 is fitted into a cylinder 16 provided on a distribution head 15. At an outer end of the distribution head 15, a vane feed pump 18 with a plurality of vanes 21 freely slidably fitted into a rotor 20 mounted on the distribution rotor 14 is provided. In such an injection pump, a screw hole 40 is formed on an end face on a pump 18 side of the distribution rotor 14 while a circular recess 41 is provided around the screw hole 40. On the other hand, a male screw 42 is formed on an end face of the rotor 20, and this is screwed into the screw hole 40 on the upper face wherein with the end face 20a of the rotor 20 and the distribution rotor end face 14b contacting with each other inside the recess 41, the rotor 20 is tightened to the distribution rotor 14 with specific torque.