An objective is to provide a circular acceleration apparatus that can accelerate higher currents as well as avoid complex controlling of a deflecting magnetic field generated by an electron deflection unit. The circular acceleration apparatus is provided, which comprising a circular accelerator 2 including an electron acceleration unit 13 and a deflection-magnetic-field generating unit 14; an electron generator 1, to which a pulsed voltage is applied, to generate electrons for injecting to the circular accelerator 2; and a circuit element which generates the pulsed voltage for providing to the electron generator 1 by making the pulsed voltage applied to the electron generator 1 have at least one of a slow rising edge and a slow falling edge.