A radio frequency power source device for delivering AC voltage outputs in antiphase with each other, with respect to ground potential, from two output ends, the device comprising: an AC power source, a radio frequency output circuit configured to convert source voltage from the AC power source into radio frequency voltage at a given frequency and to deliver the radio frequency voltage, and a voltage divider configured to divide the radio frequency voltage delivered from the radio frequency output circuit into AC voltage outputs in antiphase with each other, with respect to ground potential, wherein the voltage divider comprises a series circuit (5, 15) comprising a first capacitive element (Ca) and a second capacitive element (Cb) connected in series, the series circuit being arranged such that a middle point between output ends of the radio frequency output circuit is at the ground potential, and a changeover circuit (6, 16) configured to connect, by switching, one of the output ends of the radio frequency output circuit or the ground potential with at least either one of the first and second capacitive elements of the series circuit such that, in use, a ratio between voltages across each of the two capacitive elements varies with respect to the ground potential, and such that, in use, high voltage and low voltage are delivered by said switching; wherein the changeover circuit comprises a switch circuit, the switch circuit being arranged, in use, to short-circuit or open-circuit between the output end of the radio frequency output circuit on one capacitive element side and the ground potential, across at least either one of the two capacitive elements (Ca, Cb) of the series circuit, such that, in use, a short-circuiting operation of the switch circuit makes voltage to zero on the output end of the radio frequency output circuit on the one capacitive element side, and sets a voltage output on the output end on the other capacitive element side, as the voltage output of the radio frequency output circuit, and such that, in use, an open-circuiting operation of the switch circuit sets the voltage outputs obtained by dividing the voltage output of the radio frequency output circuit on both capacitive element sides in accordance with capacities of the two capacitive elements, as the voltage outputs of the radio frequency output circuit on both the capacitive element sides. an AC power source, a radio frequency output circuit configured to convert source voltage from the AC power source into radio frequency voltage at a given frequency and to deliver the radio frequency voltage, and a voltage divider configured to divide the radio frequency voltage delivered from the radio frequency output circuit into AC voltage outputs in antiphase with each other, with respect to ground potential, wherein the voltage divider comprises a series circuit (5, 15) comprising a first capacitive element (Ca) and a second capacitive element (Cb) connected in series, the series circuit being arranged such that a middle point between output ends of the radio frequency output circuit is at the ground potential, and a changeover circuit (6, 16) configured to connect, by switching, one of the output ends of the radio frequency output circuit or the ground potential with at least either one of the first and second capacitive elements of the series circuit such that, in use, a ratio between voltages across each of the two capacitive elements varies with respect to the ground potential, and such that, in use, high voltage and low voltage are delivered by said switching; wherein the changeover circuit comprises a switch circuit, the switch circuit being arranged, in use, to short-circuit or open-circuit between the output end of the radio frequency output circuit on one capacitive element side and the ground potential, across at least either one of the two capacitive elements (Ca, Cb) of the series circuit, such that, in use, a short-circuiting operation of the switch circuit makes voltage to zero on the output end of the radio frequency output circuit on the one capacitive element side, and sets a voltage output on the output end on the other capacitive element side, as the voltage output of the radio frequency output circuit, and such that, in use, an open-circuiting operation of the switch circuit sets the voltage outputs obtained by dividing the voltage output of the radio frequency output circuit on both capacitive element sides in accordance with capacities of the two capacitive elements, as the voltage outputs of the radio frequency output circuit on both the capacitive element sides.