<p>A boiler/turbine plant controlling apparatus comprises a circuit for driving a turbine inlet steam flow regulator valve (16) on the basis of a difference between a load command signal adjusted by a thermal stress value of a turbine (15) and an actually measured output signal of a plant; a circuit for driving a boiler feed water flow regulator valve (13) on the basis of a difference between a value which is obtained by adding a boiler feed water amount with a super heater feed water amount and a value represented by a boiler input command signal; a circuit for driving a fuel flow regulator valve (20) in accordance with an actually measured fuel amount and a fuel command signal corrected by a difference signal between a primary steam temperature setting signal and a steam temperature signal representative of a primary steam temperature measured value; a circuit for driving a super heater water feed valve (22) on the basis of a difference value between the primary steam temperature setting signal and the steam temperature signal; a circuit for calculating a steam temperature drop through the steam flow regulator valve 16) on the basis of an opening degree of the steam flow regulator valve (16) disposed at an inlet of the turbine 15) and a temperature and pressure of steam at the inlet of said steam flow regulator valve (16); and a circuit for correcting the steam temperature setting signal on the basis of the calculated value of the calculating means.</p>
