A system design apparatus has a metamodel definition unit that generates a second metamodel based on a first metamodel described using a modeling language, the second metamodel including the first metamodel, a metamodel of a condition class which describes a condition, and a metamodel which describes an association between the condition class and a trace in order to distinguish presence or absence of the condition with respect to the trace, a model construction unit that constructs a model according to the second metamodel, and a script file generation unit that generates a script file corresponding to the model.