The present disclosure relates to a plasma generator having a matching apparatus for matching impedances, and an impedance matching method. The plasma generator includes an RF power supply unit, a load device part including a standard load having a predetermined impedance and an antenna-plasma device configured to generate plasma, and a matching unit configured to connect the RF power supply unit to any one of the antenna-plasma device or the standard load, and match impedances of the RF power supply unit and the antenna-plasma device when the RF power supply unit is connected to the antenna-plasma device, wherein the matching unit is configured to detect a parasitic impedance according to parasitic components inside a circuit by connecting the standard load and the RF power supply unit, connect the antenna-plasma device, when the parasitic impedances are detected, calculate reactance required for the impedance matching, and change capacitance.