A device controller controls an acceleration-related devices and an extraction-related devices of an accelerator for accelerating and extracting a particle beam, in such a way that the controller checks, at a time point when receiving a master clock pulse, that preparation for operating the acceleration-related devices is completed and then commands the acceleration-related devices to operate in accordance with an operation pattern corresponding to a prescribed energy of the particle beam, and commands the acceleration-related devices to operate in accordance with an extracting operation pattern when an extraction enable signal indicating that the particle beam reaches the prescribed energy is turned ON and an extraction-related device setting-status signal indicating that completion of setting the extraction-related devices for the prescribed energy is ON.