A wireless power receiving device includes a receiving coil that receives AC power through an AC magnetic field, a rectification circuit that converts the AC power received by the receiving coil into DC power and outputs the obtained DC power to a load, a filter circuit provided between the rectification circuit and the load, an input voltage detection circuit that detects the input voltage of the filter circuit, an output voltage detection circuit that detects the output voltage of the filter circuit, a target voltage generation circuit that generates a second target voltage that is a target value of the input voltage based on the output voltage and a first target voltage that is a target value of the output voltage, and a receiving-side transmitter that transmits difference information indicating the difference between the input voltage and the second target voltage to the wireless power transmitting device.