Abstract: A turbine control device which compensates for non-linearity of the degree-of-opening/flow-rate characteristic of a regulating valve. The device has a turbine rotation speed detector, a calculator to determine a desired flow rate based on a predetermined rotation speed and the detected speed, a valve for controlling the flow rate with a variable degree of opening, a flow rate detector, a memory unit for memorizing combinations of the detected flow rate and respective degrees of opening of the valve, a converter for converting the desired flow rate into a valve opening command signal based on the memorized combinations of the flow rate and respective degrees of opening of the valve, and a servo controller for the valve.