1. A computer-readable, non-transitory medium storing a program for causing a computer to execute a procedure, said procedure comprising: obtaining values of evaluation indicators by generating a plurality of sets of values of design parameters and causing a simulator to carry out simulation for each of said plurality of sets; generating a first model expression having a first order and representing a relationship between said evaluation indicators and said design parameters and a second model expression having a second order higher than said first order and representing a relationship between said evaluation indicators and said design parameters, and storing said first model expression and said second model expression into a model expression storage unit; calculating values of said design parameters according to a quantifier elimination method, from said first model expression stored in the model expression storage unit and a predetermined constraint, said design parameters realizing an optimum solution of said first model expression, and storing the calculated values of said design parameters into a design parameter value storage unit; identifying a design parameter whose value stored in said design parameter value storage unit is identical to an upper limit value or a lower limit value, which is included in said predetermined constraint, and transforming said second model expression by substituting said upper limit value or said lower limit value, as a value of said identified design parameter, for said second model expression stored in said model expression storage unit; and calculating values of said design parameters in the transformed second model expression, which realize an optimum solution of said transformed second model expression, from said transformed second model expression and a constraint relating to said design parameters in the transformed second model expression, and storing the calculated values of said design parameters in the transformed second model expression into said design parameter value storage unit.