A magnetic resonance wireless power supply device utilizing PT symmetry, the magnetic resonance wireless power supply device including a power supply side resonance circuit including a power supply coil and a power receiving side resonance circuit including a power receiving coil. An inverter 3 and a sensor 4 are connected to the power supply side resonance circuit 3. A switch timing, which is the time for turning on or turning off switching elements inside the inverter 3, is determined based on pulses generated by signals after the phase relationship is adjusted by a phase adjustment circuit 30. Thus, one of the two resonance loops is selected and fixed.