PURPOSE: To provide a fuel injection device which can obtain stable and small injection amount prior to main injection, and obtain the stable and small injection amount irrespective of rotation of an engine.

CONSTITUTION: A solenoid valve 20 is arranged on the way of a fuel supply passage 34 leading to a compression chamber 15 of a fuel injection pump 1. In a fuel injection device, a fuel injection amount is adjusted by opening and closing the solenoid valve 20. A valve body 23 is moved until it seats a valve seat 24 during pre-injection process prior to main injection. This fuel injection device has a leak port 42 for leaking fuel inside the compression chamber 15. The timing for leaking the fuel inside the compression chamber 15 is matched with the timing for throttling a fuel supply passage 34 with the valve body 23 seating the valve seat 34 through the leak port 42. Motion of the valve body 23 is stabilized while proper and small pre-projection amount is obtained.