In a control system for a power steering device in which a power steering component in a steering system of a vehicle is adjusted to a desired power steering component, a vehicle speed sensor 41 for detecting a travelling speed V of the vehicle and a steering lock angle sensor for detecting a steering lock angle ha of the vehicle are provided. A lateral acceleration calculating unit calculates a lateral acceleration Gy from the vehicle speed V and the steering lock angle ha and also determines the product V . Gy from the vehicle speed V and lateral acceleration Gy. A fuzzy logic calculation unit specifies the desired power steering component according to a fuzzy logic rule using the vehicle speed V and the product V . Gy as input conditions (membership functions). As a result, a control system and a control method for controlling a power steering device are provided which indicate an optimum steering characteristic as a reaction to the travelling state of the vehicle.
