To effectively obtain an optimization solution for a group while adapting the method to plural evaluation functions and leaving a variety of solid bodies having high evaluated values by sectioning a generation into periods and setting evolution conditions by the period when an optimization problem is solved by using genetic algorithm.

When the genetic algorithm is applied, a period cycle condition table (condition setting table) 7 is provided and various evolution conditions can be set and applied, period by period, so solid bodies and groups having good evaluated values can be obtained by the genetic algorithm capable of obtaining solid bodies and groups matching plural evaluation functions. Further, this genetic algorithm can make a group having diverse solid bodies to evolve by cyclically applying plural selecting methods, breeding methods, decussating methods, and mutating methods.