A parameter adjusting device configured to adjust a great number of parameters of a physical model by a genetic algorithm using multiple processing units within a short time. A parameter adjusting device comprises a processing assignment means wherein a part of a multiple processing means is assigned to search processing by a local search method, and assigns the processing of the local search to a low-performance processor. Also, the parameter adjusting device collects an interim result of the search by a genetic algorithm, and uses it for the search processing by the local search method. Through parallelization and efficiency of an adjusting processing by effectively utilizing the resource in the system, the parameter adjusting device can determine the group of the most appropriate parameters within a short time.