To provide a fuel injection pump for an engine in which the diameter of a plunger can be increased without enlarging a constitution.

In this pump, a holder part 21 in the form of a flange is formed integrally with a cylindrical barrel part 22 to form an element barrel 20, so that the diameter of a plunger can be relatively increased without enlarging a constitution or decreasing the thickness of the barrel part 22. Accordingly, the pressure supply efficiency of fuel is improved to inject the fuel under high pressure and the atomization of injection fuel is urged to improve the emission of exhaust air. Since a slip-off preventing pin is inserted into a pump housing 11 below the element barrel 20, a step part for supporting an upper sheet 41 may not be formed in an inner hole 11b. Thus, since the form of the inner hole 11b of the pump housing 11 can be made simple, the pump housing 11 can be easily worked and the number of manufacture steps can be reduced.