The present invention provides a storage subsystem capable of preventing abnormal temperature rise within the subsystem and realizing an efficient cooling effect. Therefore, the storage subsystem has two or more controllers having two or more temperature sensors, and each controller determines a provisional rotational speed based on the value of the temperature sensors. One controller out of the multiple controllers operates as the master controller, and the other controllers (slave controllers) transmit a provisional rotational speed determined in its own system to the master controller. The master controller determines a greater value of the provisional rotational speed information received from the slave controllers and the provisional rotational speed determined in its own system as the final rotational speed of the fan.