An analysis of a symmetric wireless power transfer circuit is presented for a frequency control method to obtain maximum load power. Wireless power transfer for small medical devices such as artificial cardiac pacemakers, cochlear implants, and Holter monitors are very important. The power consumption can be reduced with simplification of the power control circuit in the devices. We have proposed a method to obtain a maximum load power in a symmetric magnetic resonance wireless power transfer system by a frequency control using the measurement of the current on the transmitter side.