It is so configured that a control unit(20) is provided with, an operation pattern retaining section(25) that retains a plurality of operation patterns(OP-S,OP-L) each given as a pattern of operation to be periodically repeated by an accelerator(10), the operation patterns having respective operation conditions adjusted to have different times (To) that allow emission of an particle beam B, and to cause a deflection electromagnet(13) in the accelerator(10) to have an intended magnetic field intensity even under a presence of a hysteresis an irradiation condition reading section(22) for a plurality of slices resulted from partitioning an irradiation target in a depth direction, that reads an irradiation condition for each of the slices an operation pattern selection section(23) that selects the operation pattern suitable for each of the slices from among the plurality of operation patterns, on the basis of the read irradiation condition and a main control section(21) that controls, for each of the slices, the accelerator(10) on the basis of the selected operation pattern and an irradiation device(40) on the basis of the irradiation condition.
