A high-frequency power device comprising: a transformer; and a high-frequency voltage generating circuit configured to feed a high-frequency voltage to a primary coil (Np) of the transformer, the primary coil (Np) forming an electric feeder section; characterized in that: there is further provided a divider (C 1,C 2) configured to divide a voltage across opposite terminals of a secondary coil (Ns) of the transformer or opposite terminals of an element of a circuit associated with the secondary coil (Ns) at a predetermined voltage ratio, the element being applied with a high voltage; the divider is a series circuit in which a first impedance element (C 1) and a second impedance element (C 2) are connected in series; the first impedance element (C 1) is an impedance element connected to a higher potential side of the opposite terminals of the secondary coil (Ns) of the transformer or to a higher potential side of the circuit associated with the secondary coil (Ns), while the second impedance element (C 2) is an impedance element connected to a lower potential side of the opposite terminals of the secondary coil (Ns) or to a lower potential side of the circuit associated with the secondary coil (Ns); and the first impedance element (C 1) has an impedance represented by Za and the second impedance element (C 2) has an impedance represented by Zp, the ratio of Za/Zp which is the ratio of the impedance of the first impedance element (C 1) to the impedance of the second impedance element (C 2) being equal to the ratio of Cp/Ca which is the ratio of a second equivalent capacitance to ground Cp produced between the lower potential side and the earth ground to a first equivalent capacitance to ground Ca produced between the higher potential side and the earth ground. a transformer; and a high-frequency voltage generating circuit configured to feed a high-frequency voltage to a primary coil (Np) of the transformer, the primary coil (Np) forming an electric feeder section; characterized in that: there is further provided a divider (C 1,C 2) configured to divide a voltage across opposite terminals of a secondary coil (Ns) of the transformer or opposite terminals of an element of a circuit associated with the secondary coil (Ns) at a predetermined voltage ratio, the element being applied with a high voltage; the divider is a series circuit in which a first impedance element (C 1) and a second impedance element (C 2) are connected in series; the first impedance element (C 1) is an impedance element connected to a higher potential side of the opposite terminals of the secondary coil (Ns) of the transformer or to a higher potential side of the circuit associated with the secondary coil (Ns), while the second impedance element (C 2) is an impedance element connected to a lower potential side of the opposite terminals of the secondary coil (Ns) or to a lower potential side of the circuit associated with the secondary coil (Ns); and the first impedance element (C 1) has an impedance represented by Za and the second impedance element (C 2) has an impedance represented by Zp, the ratio of Za/Zp which is the ratio of the impedance of the first impedance element (C 1) to the impedance of the second impedance element (C 2) being equal to the ratio of Cp/Ca which is the ratio of a second equivalent capacitance to ground Cp produced between the lower potential side and the earth ground to a first equivalent capacitance to ground Ca produced between the higher potential side and the earth ground. there is further provided a divider (C 1,C 2) configured to divide a voltage across opposite terminals of a secondary coil (Ns) of the transformer or opposite terminals of an element of a circuit associated with the secondary coil (Ns) at a predetermined voltage ratio, the element being applied with a high voltage; the divider is a series circuit in which a first impedance element (C 1) and a second impedance element (C 2) are connected in series; the first impedance element (C 1) is an impedance element connected to a higher potential side of the opposite terminals of the secondary coil (Ns) of the transformer or to a higher potential side of the circuit associated with the secondary coil (Ns), while the second impedance element (C 2) is an impedance element connected to a lower potential side of the opposite terminals of the secondary coil (Ns) or to a lower potential side of the circuit associated with the secondary coil (Ns); and the first impedance element (C 1) has an impedance represented by Za and the second impedance element (C 2) has an impedance represented by Zp, the ratio of Za/Zp which is the ratio of the impedance of the first impedance element (C 1) to the impedance of the second impedance element (C 2) being equal to the ratio of Cp/Ca which is the ratio of a second equivalent capacitance to ground Cp produced between the lower potential side and the earth ground to a first equivalent capacitance to ground Ca produced between the higher potential side and the earth ground.