Even in a case where a disturbance is applied from an adjacently disposed power supply circuit or the like, in order to realize a reduction in ripple, a high-voltage power supply device is configured to include a drive circuit, a transformer that boosts an output voltage of the drive circuit, a boost circuit that further boosts a voltage boosted by the transformer, a shield that covers the transformer and the boost circuit, a filter circuit that filters, smoothes, and outputs a high voltage output from the boost circuit, and an impedance loop circuit configured by connection of a plurality of impedance elements into a loop shape. A grounding point of the boost circuit, a grounding point of the shield, and a grounding point of the filter circuit are configured to be grounded via the impedance loop circuit, and this is applied to a high-voltage power supply unit that applies a high voltage to an electron gun of a charged particle beam apparatus.