There is provided a method of updating a setting value of a variable parameter, the method including: obtaining a time-series data of control input and a time-series data of control output observed in control with a controller; calculating a value of the variable parameter which minimizes an output value of an evaluation function based on the obtained time-series data of the control input and the control output; and updating the setting value of the variable parameter to the calculated value of the variable parameter. The evaluation function includes a first function part in which a first norm or a second norm changes depending on the value of the variable parameter, and a second function part of which specific frequency band has an amount, by which the output value of the evaluation function is increased, larger than that of any other frequency band.