One embodiment of a particle accelerator includes: a particle source from which a particle beam is extracted with a beam pulse width of not greater than 2 &musec a linear accelerator for accelerating the particle beam extracted from the particle source a synchrotron for receiving the particle beam transported thereto from the linear accelerator and causing the particle beam to circulate in order to accelerate it until it gets to a predetermined energy level a bump electromagnet for shifting the circulating path of the particle beam each time it makes a full turn and a control unit for controlling the extent of magnetic excitation of the bump electromagnet and for controlling the timing of magnetic excitation of the bump electromagnet according to the pulse timing of the particle source.
