Provided is a wireless power supply system that supplies AC power to a power reception apparatus by using resonance of an electromagnetic field between a power transmission element and a power reception element. The wireless power supply system includes a changing circuit that changes a frequency of AC power supplied to the power transmission element, and a control device including (A) a frequency changing unit that adjusts the changing circuit to change the frequency of AC power supplied to the power transmission element in a manner capable of being controlled, (B) a frequency measurement unit that measures a first frequency and a second frequency when a state of power supply to the power reception apparatus varies between a state in which AC power is actually supplied and a state in which AC power is not supplied in accordance with the changing of the frequency of AC power, and (C) a frequency determination unit that determines the frequency of AC power during supply of AC power to the power reception apparatus to a frequency between the first frequency and the second frequency. According to this, the frequency of AC power during power supply can be appropriately adjusted, and thus it is possible to efficiently supply power to the power reception apparatus.