A high-frequency control device for an accelerator to control a high-frequency which is applied to an acceleration cavity of an accelerator which is adapted to generate a particle beam to be used for a particle beam therapy, wherein the high-frequency control device for an accelerator comprises - a hard disk drive memory which is adapted to store pattern data of a high-frequency to be applied for each combination of energy and intensity of the generated particle beam, and - a local memory, which is adapted to read a plurality of pattern data of a high-frequency for each patient together with the sequential order of changing energy and intensity from the hard disk drive memory and to store data in order to perform a scanning irradiation method in which a layered particle beam irradiation region in a depth direction of an affected part of the patient is formed sequentially by changing energy and intensity of the particle beam sequentially to irradiate the affected part of the patient which is an irradiation subject with the particle beam, and which is adapted to read out data faster than the hard disk drive memory, further comprising: - a command value checking part which is adapted to check whether a command value from an irradiation system control device which is adapted to control a particle beam irradiation device for irradiating the affected part which is the irradiation subject for each time when energy and intensity of the particle beam are changed, is in agreement with pattern data which is sent out from the local memory or not, wherein in a case where it is judged such that a command value from the irradiation system control device is not in agreement with pattern data which is sent out from the local memory, the accelerator is adapted to be operated according to subsequent pattern data of energy and intensity, and while the operation, data in the local memory is reread until the data pattern is in agreement with the command value. - a hard disk drive memory which is adapted to store pattern data of a high-frequency to be applied for each combination of energy and intensity of the generated particle beam, and - a local memory, which is adapted to read a plurality of pattern data of a high-frequency for each patient together with the sequential order of changing energy and intensity from the hard disk drive memory and to store data in order to perform a scanning irradiation method in which a layered particle beam irradiation region in a depth direction of an affected part of the patient is formed sequentially by changing energy and intensity of the particle beam sequentially to irradiate the affected part of the patient which is an irradiation subject with the particle beam, and which is adapted to read out data faster than the hard disk drive memory, - a command value checking part which is adapted to check whether a command value from an irradiation system control device which is adapted to control a particle beam irradiation device for irradiating the affected part which is the irradiation subject for each time when energy and intensity of the particle beam are changed, is in agreement with pattern data which is sent out from the local memory or not,