To provide a setting method of experimental planning for control parameters capable of setting an additional experimental point efficiently and accurately.

The setting method of experimental planning for the control parameters comprises a step (S3) of determining whether missing values is included in a first predetermined number of experimental points, and steps (S4-S9) of setting a second predetermined number of additional experimental points. Regarding how a plurality of control parameters are varied with reference to the missing values, a plurality of retrieving directions are previously assigned to a plurality of priorities. The step of setting the additional experimental points comprises steps (S4-S8) of applying the plurality of retrieving directions in the descending order of the priorities and setting a candidate of the additional experimental points until the control parameter of the missing values provides a required number, and a step (S9) for selecting the additional experimental points from the required number of candidates.