High-frequency power supply system

Techniques for suppressing an increase in reflected wave power (reflection coefficient) due to IMD are proposed. A high-frequency power supply system for providing a high-frequency power to a connected load includes: a bias power supply which outputs a bias power at a first frequency; a source power supply which outputs a source power at a second frequency higher than the first frequency; and a matching unit including an impedance matching circuit which acquires the bias power and the source power and matches an impedance of the source power supply side with an impedance of the load side. The source power supply determines a delay setting value indicating the timing of starting a frequency variation process with respect to the source power, performs the frequency variation process using the delay setting value and the value of the first frequency, and outputs a frequency-varied source power to the matching unit.