The present invention relates to an apparatus and method capable of performing immediate impedance matching according to changes of a distance and positions between TX/RX coils. The present invention includes: an impedance adjustment unit including a voltage-controlled variable capacitance device; a power detector configured to detect a reflection signal which enters the transmitter or receiver when there is no impedance matching to measure a magnitude of the reflection signal and convert the reflection signal into a DC signal; a multiplier configured to multiply the DC signal with a periodic signal; an integrator configured to accumulate and add a signal in which the DC signal and the periodic signal are multiplied; and a voltage summer configured to sum a signal output from the integrator with a reference voltage to calculate a capacitance control voltage to be applied to the voltage-controlled variable capacitance device.