NON-CONTACT POWER SUPPLY DEVICE

In a non-contact power supply device, a power reception device includes a first resonant circuit that resonates at a first frequency, a voltage detection circuit that measures an output voltage from the first resonant circuit to obtain a measurement value of the output voltage, and a transmitter that transmits a signal including information representing the measurement value to a power transmission device. The power transmission device includes a second resonant circuit that resonates at a second frequency lower than the first frequency, a power supply circuit that supplies AC power having an adjustable switching frequency to the second resonant circuit, a receiver that receives the signal including the information representing the measurement value, and a control circuit that controls the switching frequency in accordance with the measurement value, such that the second resonant circuit and the power supply circuit continue a soft switching operation.