PURPOSE: To ensure stable injection timing control at all times over a wide range of fuel pressure regardless of opening/closing of a control valve by separating a pressure-controlled low pressure chamber from a high pressure chamber, and delaying relief of fuel pressure from the high pressure chamber.

CONSTITUTION: When a feed pump 3 is driven while being interlocked with rotation of an engine 4, fuel is pressure-supplied from the discharging side of the feed pump 3 into a pump housing 2, and fuel pressure in the pump housing 2 and that in a high pressure chamber 11 come up to the same level. In the case when a TCV 15 is opening/closing controlled by means of an ECU21 under, for example, a large duty ratio, a fuel flow amount led from the pump housing 2 into a low pressure chamber 12 through a first passage 14 is increased. Hence, a timer piston 7 is pushed and moved toward the high pressure chamber 11 side by pressure-increase in a low pressure chamber 12 and energizing force of a timer spring 13. As a result, a roller ring 10 is rotated anticlockwise by a slide pin 9, and the injection timing of a fuel injection pump is controlled so as to delay the timing of injection for example.