PURPOSE: To provide main injection and additional injection during exhaust stroke by reciprocating the plunger of a fuel injection pump by the identical number as the number of cylinders.

CONSTITUTION: The fuel pressurized by a plunger 46 is discharged in order to respective fuel outflow ports 71a, 71b, 71c, 71d through a fuel discharge passage 69 and a main injection fuel discharge port 70a in a plunger 46, and the discharged fuel is injected from a corresponding Fuel injection valve. In the plunger 46, a sub injection fuel discharge port 70b is formed at an angular interval a little larger than 90 degree from the sub injection fuel discharge port 70b. The fuel discharged from the sub injection fuel discharge port 70b at the time of main injection is supplied to the inside of the combustion chamber of the cylinder under an exhaust stroke.