Many problems which are useful for engineering are usually formulated as function optimization problems. In this paper, we consider function optimization problem as combinatorial optimization problem. Because we sometimes deal with integer number in the design of industrial products. For solving such an optimization problem, local search methods have been proposed. But most of them search all parameters simultaneously. As the result, the search space size increases exponentially with the number of parameters. Therefore we propose a divisional local search method which is named ``Free&Freeze method'' for such a large scale optimization problem.
