PURPOSE: To increase displacement space by inserting a pair of plungers that is engaged with a cam follower arranged surrounding and is reciprocating in the radial direction, and forming a plunger hole in one plunger into which a piston in one body with the other plunger is inserted.

CONSTITUTION: The fuel pumping apparatus includes a rotary distributor element 10, a movable member 13 in the form of a sleeve mounted in an end of a drive shaft 14 driven by an engine is arranged surrounding an extension 12 of the distributor. And, a cam follower 16 composed of a roller 17 that engages with internal circumference of an annular cam ring 19 and a shoe 18 is arranged in a pair of opposite slots 15 mounted in the drive element 13. And, outer end of a pair of plungers 20, 21 inserted in a hole 22 of an element 10 is engaged with the shoe 18. A piston 33 in one body with the plunger 21 is inserted in a hole 31 formed in the plunger 20, and the space between the plunger 20 and 21 becomes a pump chamber 23.