A treatment planning apparatus includes an overall data management unit for storing a target irradiation dose distribution to be formed in an irradiation object, a broad irradiation parameter calculation unit and a scanning irradiation parameter calculation unit for cooperatively calculating and determining operational parameters for devices, such as an accelerator and an irradiation nozzle, to operate during a broad irradiation and an scanning irradiation, respectively, so that the sum of irradiation doses imparted by both broad irradiation and scanning irradiation forms the target irradiation dose distribution.
