PURPOSE: To control injection timing of fuel and a quantity of injection fuel, by controlling feed and cut timing of fuel to a plunger chamber through a selector valve and regulating pressure of the fuel in the plunger chamber.

CONSTITUTION: Fuel, fed out from a pressure control valve 15, is fed to a selector valve 19 through a pipe 18, and then supplied to an inlet 9 of a main unit 1. This selector valve 19 is driven by a digital pulse motor 20 relating to the operational state of an engine and movement of a plunger 6. In consequence, start and end timing of injection can be correctly and surely controlled in accordance with the operational state by very simple constitution.