PURPOSE: To stop an engine positively in preventing any reinjection from occurring by enlarging an opening area of a pore in an overflow valve, and installing another pore different from this pore in the overflow valve in addition.

CONSTITUTION: An overflow valve 60 for preventing pressure in a pump case from exceeding an upper limit area of pressure limits is attached to a pump housing 4. In this overflow valve 60, there are provided with a hole 61 interconnected to the pump case 12, a pore 62 interconnected each to this hole 61 and another pore 63 sufficiently larger in diameter than the pore 62. Thus, when the supply of fuel to a plunger chamber 24 is stopped by a solenoid valve 32, any reinjection is prevented from occurring and an engine can be positively stopped.