A radio-frequency voltage generator that generates radio-frequency voltage from direct-current voltage and applies the radio-frequency voltage to a load, the radio-frequency voltage generator comprising: a) a first direct-current voltage generation section for generating first direct-current voltage; b) a second direct-current voltage generation section for generating second direct-current voltage having a value different from that of the first direct-current voltage; characterized in that it further comprises: c) a transient alternating voltage generation section for oscillating transient alternating voltage having a cycle shorter than a cycle of the radio-frequency voltage, a maximum value of the transient alternating voltage being one of the first direct-current voltage and the second direct-current voltage, and a minimum value of the transient alternating voltage being the other one, starting with an initial value being the first direct-current voltage or the second direct-current voltage; and d) a voltage switch section for switching voltages applied to the load, during a cycle of the radio-frequency voltage, from the first direct-current voltage, to the transient alternating voltage the initial value of which is the first direct-current voltage, to the second direct-current voltage, to the transient alternating voltage the initial value of which is the second direct-current voltage, in this order, the voltage switch section switching the voltages applied to the load such that a time period of the transient alternating voltage becomes a multiple of a half-integer of the cycle of the transient alternating voltage and shorter than a half cycle of the radio-frequency voltage, the half-integer being equal to or greater than 1.5. a) a first direct-current voltage generation section for generating first direct-current voltage; b) a second direct-current voltage generation section for generating second direct-current voltage having a value different from that of the first direct-current voltage; characterized in that it further comprises: c) a transient alternating voltage generation section for oscillating transient alternating voltage having a cycle shorter than a cycle of the radio-frequency voltage, a maximum value of the transient alternating voltage being one of the first direct-current voltage and the second direct-current voltage, and a minimum value of the transient alternating voltage being the other one, starting with an initial value being the first direct-current voltage or the second direct-current voltage; and d) a voltage switch section for switching voltages applied to the load, during a cycle of the radio-frequency voltage, from the first direct-current voltage, to the transient alternating voltage the initial value of which is the first direct-current voltage, to the second direct-current voltage, to the transient alternating voltage the initial value of which is the second direct-current voltage, in this order, the voltage switch section switching the voltages applied to the load such that a time period of the transient alternating voltage becomes a multiple of a half-integer of the cycle of the transient alternating voltage and shorter than a half cycle of the radio-frequency voltage, the half-integer being equal to or greater than 1.5. c) a transient alternating voltage generation section for oscillating transient alternating voltage having a cycle shorter than a cycle of the radio-frequency voltage, a maximum value of the transient alternating voltage being one of the first direct-current voltage and the second direct-current voltage, and a minimum value of the transient alternating voltage being the other one, starting with an initial value being the first direct-current voltage or the second direct-current voltage; and d) a voltage switch section for switching voltages applied to the load, during a cycle of the radio-frequency voltage, from the first direct-current voltage, to the transient alternating voltage the initial value of which is the first direct-current voltage, to the second direct-current voltage, to the transient alternating voltage the initial value of which is the second direct-current voltage, in this order, the voltage switch section switching the voltages applied to the load such that a time period of the transient alternating voltage becomes a multiple of a half-integer of the cycle of the transient alternating voltage and shorter than a half cycle of the radio-frequency voltage, the half-integer being equal to or greater than 1.5.