CONTACTLESS POWER SUPPLY SYSTEM

A wireless power supply system (1) includes a power supply coil (20) installed on the ground, an inner balloon (30a) in which a power supply coil is mounted and configured to expand and contract to adjust a vertical position of the power supply coil, and an outer balloon (30b) provided to cover both the power supply coil and the inner balloon and configured to expand to occupy a space between the power supply coil and a power receiving coil (50), and wirelessly supplies power from the power supply coil to the power receiving coil. Thereby, it is possible to provide a wireless power supply system capable of realizing long-distance transmission of power without increasing the cost and size of the system.