A wireless power transmission system comprising: an oscillating section configured to convert DC energy supplied from a power generating section into RF energy with a frequency f0; a power-transmitting antenna configured to transmit the RF energy; a power-receiving antenna configured to receive at least a part of the RF energy that has been transmitted by the power-transmitting antenna; and a rectifying section configured to convert the RF energy that has been received by the power-receiving antenna into DC energy; wherein the power-transmitting antenna is a series resonant circuit; wherein the power-receiving antenna is a parallel resonant circuit; and wherein resonant frequencies fT and fR of the power-transmitting and power-receiving antennas are both set to be equal to the frequency f0 of the RF energy; wherein the wireless power transmission system further comprisesa transmitting-end control section configured to match the input impedance of the oscillating section to the output impedance of the power generating section by changing the input impedance of the oscillating section in accordance with a variation in the output impedance of the power generating section, and wherein the wireless power transmission system is configured to wirelessly transfer energy supplied from the power generating section, characterized in that the oscillating section includes multiple oscillators having respective predefined input impedance ranges, and wherein the transmitting-end control section is further configured to choose one of the oscillators according to the output impedance value of the power generating section and to make current flow through the oscillator chosen, thereby changing the input impedance of the oscillating section. an oscillating section configured to convert DC energy supplied from a power generating section into RF energy with a frequency f0; a power-transmitting antenna configured to transmit the RF energy; a power-receiving antenna configured to receive at least a part of the RF energy that has been transmitted by the power-transmitting antenna; and a rectifying section configured to convert the RF energy that has been received by the power-receiving antenna into DC energy; wherein the power-transmitting antenna is a series resonant circuit; wherein the power-receiving antenna is a parallel resonant circuit; and wherein resonant frequencies fT and fR of the power-transmitting and power-receiving antennas are both set to be equal to the frequency f0 of the RF energy; wherein the wireless power transmission system further comprisesa transmitting-end control section configured to match the input impedance of the oscillating section to the output impedance of the power generating section by changing the input impedance of the oscillating section in accordance with a variation in the output impedance of the power generating section, and wherein the wireless power transmission system is configured to wirelessly transfer energy supplied from the power generating section, characterized in that the oscillating section includes multiple oscillators having respective predefined input impedance ranges, and wherein the transmitting-end control section is further configured to choose one of the oscillators according to the output impedance value of the power generating section and to make current flow through the oscillator chosen, thereby changing the input impedance of the oscillating section.