One embodiment of a particle circular accelerator 1 includes: a beam deflector (7) for beam injections, bending electromagnets (2) that causes the beam injected from the beam deflector (7) for beam injections to circulate so as to form a circulation orbit, orbit adjusting electromagnets for injected beams (5) that shift the position of each injected beam relative to the center of the circulation orbit of the beam, quadrupole electromagnets (3) and sextupole electromagnets (4) that adjust their respective quantities of magnetic excitation at the time of a beam extraction so as to extract a beam in a resonant region off a stable reason of beams and a beam deflector (8) for beam extractions that takes out the beam extracted from the resonant region to the outside. The circular accelerator (1) injects beams from the inner side thereof and emits beams to the outer side thereof.
