PURPOSE: To inject an accurate quantity of fuel into an internal combustion engine by an arrangement wherein the flow rate of the fuel cooling a solenoid winding and then flowing out from a fuel injection device is controlled by a pressure holding valve controlled by the regulated fuel pressure to maintain the fuel pressure correctly.

CONSTITUTION: A fuel injection device 5 is supplied with a fuel kept at a constant pressure which is supplied under pressure by a fuel pump 1 and regulated by a pressure control valve 6. This fuel is supplied into a region near an injection port b of the fuel injection device 5 from where it is injected into the engine. Further, the fuel flows in the direction opposite to the injection port b to cool a solenoid winding 5a. The fuel which has cooled the solenoid winding 5a joins the surplus fuel flowing out from the pressure control valve 6 and then flows into a port f of a pressure holding valve 8. The pressure holding valve 8 is controlled by the regulated pressure of the fuel flowing thereinto through a port g so as to control the quantity of the fuel flowing out from the fuel injection device 5 thereby maintaining the fuel pressure correctly.