PURPOSE: To perform transient fuel supply and stationary fuel measurement simply and certainly, by adjusting openings of weighing valves in injection pipings in accordance with pressure differences between fuel pressures in the injection pipings connected to injection orifices and an exhaust gas pressure in a duct.

CONSTITUTION: Fuel sent under pressure from a centrifugal pump 9 is injected from respective injection orifices 2, 2a via respective weighing valves 13, 13a and respective cutoff valves 14, 14a set to plural numbers of injection pipings 3, 3a respectively. At this time, pressure differences between fuel pressures in respective injection pipings 3, 3a detected by respective sensors 15, 15a respectively, and exhaust gas pressure in a duct 1 detected by a sensor 16 are detected by a detector 17. Also, pressure difference A detected by the detector 17 and target pressure difference B are compared with each other by means of a comparator 18. As a result, when difference exists between the detected pressure difference A and the target pressure difference B, openings of respective weighing valves 13, 13a are controlled to dissolve this difference by means of a controller 19 respectively.