A non-contact feeding device comprising: a power transmission device; and a power receiving device to which power is transmitted from the power transmission device in a non-contact manner, wherein the power transmission device includes: a transmission coil configured to supply the power to the power receiving device; a power supply circuit configured to supply AC power to the transmission coil and to be capable of adjusting at least one of a switching frequency and voltage of the AC power supplied to the transmission coil; a first communicator configured to receive an output voltage abnormal signal from the power receiving device; and a control circuit configured to change at least one of the switching frequency and the voltage of the AC power supplied from the power supply circuit to the transmission coil when the first communicator receives the output voltage abnormal signal, the power receiving device includes: a resonance circuit including a receiving coil receiving the power from the power transmission device and a resonance capacitor connected in series to the receiving coil; a rectifier circuit configured to rectify the power received through the resonance circuit; a resonance suppressing coil disposed so as to be capable of being electromagnetically coupled to the receiving coil; a switch circuit connected to the resonance suppressing coil to be capable of switching between short circuit and opening of the resonance suppressing coil; a voltage detection circuit configured to measure an output voltage of the power output from the rectifier circuit and to obtain a measured value of the output voltage; a second communicator capable of communicating with the first communicator; the non-contact feeding device being characterized in that the power receiving device includes: a determination circuit configured to cause the second communicator to transmit the output voltage abnormal signal while controlling the switch circuit so as to short-circuit the resonance suppressing coil when the measured value of the output voltage becomes greater than or equal to a predetermined upper-limit threshold. a power transmission device; and a power receiving device to which power is transmitted from the power transmission device in a non-contact manner, wherein the power transmission device includes: a transmission coil configured to supply the power to the power receiving device; a power supply circuit configured to supply AC power to the transmission coil and to be capable of adjusting at least one of a switching frequency and voltage of the AC power supplied to the transmission coil; a first communicator configured to receive an output voltage abnormal signal from the power receiving device; and a control circuit configured to change at least one of the switching frequency and the voltage of the AC power supplied from the power supply circuit to the transmission coil when the first communicator receives the output voltage abnormal signal, a transmission coil configured to supply the power to the power receiving device; a power supply circuit configured to supply AC power to the transmission coil and to be capable of adjusting at least one of a switching frequency and voltage of the AC power supplied to the transmission coil; a first communicator configured to receive an output voltage abnormal signal from the power receiving device; and a control circuit configured to change at least one of the switching frequency and the voltage of the AC power supplied from the power supply circuit to the transmission coil when the first communicator receives the output voltage abnormal signal, the power receiving device includes: a resonance circuit including a receiving coil receiving the power from the power transmission device and a resonance capacitor connected in series to the receiving coil; a rectifier circuit configured to rectify the power received through the resonance circuit; a resonance suppressing coil disposed so as to be capable of being electromagnetically coupled to the receiving coil; a switch circuit connected to the resonance suppressing coil to be capable of switching between short circuit and opening of the resonance suppressing coil; a voltage detection circuit configured to measure an output voltage of the power output from the rectifier circuit and to obtain a measured value of the output voltage; a second communicator capable of communicating with the first communicator; a resonance circuit including a receiving coil receiving the power from the power transmission device and a resonance capacitor connected in series to the receiving coil; a rectifier circuit configured to rectify the power received through the resonance circuit; a resonance suppressing coil disposed so as to be capable of being electromagnetically coupled to the receiving coil; a switch circuit connected to the resonance suppressing coil to be capable of switching between short circuit and opening of the resonance suppressing coil; a voltage detection circuit configured to measure an output voltage of the power output from the rectifier circuit and to obtain a measured value of the output voltage; a second communicator capable of communicating with the first communicator; the non-contact feeding device being characterized in that the power receiving device includes: a determination circuit configured to cause the second communicator to transmit the output voltage abnormal signal while controlling the switch circuit so as to short-circuit the resonance suppressing coil when the measured value of the output voltage becomes greater than or equal to a predetermined upper-limit threshold.