A particle accelerator that is a synchrocyclotron accelerating charged particles and which includes an acceleration electrode that accelerates the charged particles; a high frequency power source that supplies the electric power to the acceleration electrode; a control unit that adjusts the frequency of the electric power supplied from the high frequency power source based on energy of the charged particle which is accelerated; and a matching circuit that has a coil and a capacitor, and performing impedance matching between the acceleration electrode and the high frequency power source, wherein the matching circuit has an inductance adjustment unit electrically adjusting the inductance of the coil.