PURPOSE: To double the oil feeding rate of a fuel injection pump with respect to the same cam profile, with a simple structure, by making the number of rotations of a face cam-equal to that of an engine, and, at the same time, making the number of convexity of the face cam 1/2 of the number of cylinders of the engine.

CONSTITUTION: When a drive shaft 4 is rotated with the same number of rotations as that of an engine, both a face cam 22 and a plunger 21 are also rotated with the same number of rotations. When a convexity 24 axially moves the plunger 21 through rotation of the face cam 22, a fuel is caused to pass through a distribution groove 13, an outlet port 12, a two-way control valve 28, and a fuel distribution passage 14-1 to be force fed to a fuel injection nozzle for a first air cylinder, thus being injected. On the other hand, when the face cam 22 is rotated through an angle of 180°, another convexity portion 26 causes the plunger 21 to be axially moved whereupon the fuel is force fed to the fuel injection nozzle for a third air cylinder. By making the number of the convexities 24, 26 half the number of the air cylinders, the speed of the face cam 22 and the oil-feeding rate of the fuel injection pump is doubled as compared with those in the prior art.