PURPOSE: To perform correction in good accuracy, by controlling pressure in a timer chamber with a solenoid valve, controlling injection timing with an electronic timer electronic control unit, providing a correcting terminal to said control unit and correcting initial setting through earth-connection of said correcting terminal.

CONSTITUTION: A fuel injection pump is mounted with alignment to the timing mark of an engine, and lead-lag timing with respect to required injection timing is checked at idle operation, then a correction terminal T1 or T2 is connected to a GND terminal 7 to perform correction. For instance, in case of 0.5°CA under, the correction terminal T1 is connected to the GND terminal 7 to obtain a logical O signal, and output of a timer solenoid valve is changed to advance injection timing 0.5°CA in a full range of operation, thus a timer position is advanced 0.5°CA and corrected. In this way, initial setting can be corrected only by connecting the terminal of a microcomputer 10 to the earth, and workability and accuracy can be improved.