PURPOSE: To provide an automatic control method with which the satisfactory controlled result can be obtained and disturbance suppressing characteristics are improved even when a controlled object has non-linear characteristics.

CONSTITUTION: A virtual target value Rn+1 and a virtual controlled variable Yn+1 are provided by respectively adding a parameter λ, which satisfies the condition of λ>rmax>0, to a target value rn+1 and a controlled variable y'n+1, generality is added while defining these values as positive values, a product Δun+1 of a parameter β.Kn+1 (β=+1 when the controlled object has positive characteristics but β=-1 when it has negative characteristics), control deviation =Rn+1--Yn+1=rn+1-y'n+1 and n-th manipulated variable un is calculated, and a control operation is performed with that product Δun+1 as the increased component of an (n+1)th manipulated variable. The condition of un+1=un+Δun+1 is established for a normal system and the condition of un+1=Δun+1 s established for a non-normal system.