This DC pulse power supply device comprises a voltage clamper including a capacitor that is connected in parallel to a DC reactor in a chopper circuit provided in a pulsing unit in order to suppress increases in the surge voltage resulting from the leakage inductance of the DC reactor. During the start-up of pulsing operation, which is the initial stage of the pulse mode, the frequency of the pulsing operation of the chopper circuit is controlled over the period until the capacitor voltage is charged to a sufficient voltage to reset the magnetic saturation of the DC reactor.