PURPOSE: To quickly adjest a system when process is rapidly fluctuated by executing time delay compensation control based on a Smith prediction coordinate system.

CONSTITUTION: A means 37 connected between an addition elements S and a controller C is provided and the controller receives an error signal E from the output of the addition elements S and supplies the output for deciding a closed loop timer constant αi expressed by αi=f(Ei) as a function of the error signal. The error signal Ei decides the value of the closed loop time constant αi of a Smith prediction controller in accordance with a functional relation to be inverse relation. In other words, the value of the closed loop time constant becomes smaller when the value of the error signal Ei is large and the value of the closed loop time constant becomes larger when the value of the error signal Ei is comparatively small. Moreover, the relation between the error signal and the closed loop time constant can be expressed by a reverse relation in which the closed loop time constant is an inverse relation to the system error.