PURPOSE: To improve a response to the wide fluctuation of a system head and the performance of a control system in a feed water pump at a power plant by using the system head fluctuation of said pump as a lead signal for a delivery volume control system.

CONSTITUTION: A deviation signal is obtained by the collation of a feed volume target 3 determined on the basis of a plant output order signal 1 and a feed volume signal from a feed volume detector 4. This deviation signal passes through a PID operator 6 and changes to a speed order signal 7 for a steam turbine 19 to drive a feed water pump 20. On the other hand, a speed lead order signal 10 is outputted from a system head signal given by a pressure detector 8 and the feed volume target 3. And this speed lead order signal 10 is synthesized with said speed order signal 7 and changes to a final order signal 14, thereby controlling the steam turbine 19.