Abstract: A problem solver apparatus for solving optimization problems, which finds better solutions at a higher speed by utilizing both genetic algorithms and OR-based techniques. When an optimization problem is given to the problem solver apparatus, a searching strategy optimization unit creates a population of individuals using a genetic algorithm. Each individual has a chromosome to indicate a solution searching strategy. Upon receipt of such a population, a solution searching unit searches for solutions according to the strategies respectively indicated by the chromosomes of the individuals, thus obtaining candidate solutions. This group of candidate solutions is returned to the searching strategy optimization unit. The searching strategy optimization unit calculates fitness values of respective candidate solutions in the received candidate group. The searching strategy optimization unit applies some genetic operators to the individuals, thereby producing a new generation population.