A parking assist system, - to be used in a wireless power supply system which is configured in order to perform wireless power supply between a ground-side coil unit and a vehicle-side coil unit, said parking assist system - configured to set in advance a first region (α) in which the power supply is possible when a gap (Gap) between the vehicle-side coil unit and the ground-side coil unit is maximum (Zmax) and a second region (α+β) in which the power supply is possible when the gap (Gap) is minimum (Zmin), - said parking assist system comprising: - a vehicle position determination unit (4, 21) configured to determine a position of a vehicle relative to each of the a first region (α) and the second region (α+β); - a supply possibility determination unit (4, 21) configured to determine possibility of the power supply based on a result of the determination by the vehicle position determination unit (4, 21); - a display unit configured to display a result of the determination by the supply possibility determination unit (4, 21) for an occupant of the vehicle; and - a distance measuring unit (25a, 25b) configured to measure the gap (Gap), wherein when the position of the vehicle is determined to be outside the first region (α) and inside the second region (α+β), the supply possibility determination unit (4, 21) is configured (i) to determine the possibility of the power supply based on a gap measurement value measured by the distance measuring unit (25a, 25b) and (ii) to determine that supply of power is possible when a measurement value of the gap (Gap) is between minimum (Zmin) and maximum (Zmax). - to be used in a wireless power supply system which is configured in order to perform wireless power supply between a ground-side coil unit and a vehicle-side coil unit, said parking assist system - configured to set in advance a first region (α) in which the power supply is possible when a gap (Gap) between the vehicle-side coil unit and the ground-side coil unit is maximum (Zmax) and a second region (α+β) in which the power supply is possible when the gap (Gap) is minimum (Zmin), - said parking assist system comprising: - a vehicle position determination unit (4, 21) configured to determine a position of a vehicle relative to each of the a first region (α) and the second region (α+β); - a supply possibility determination unit (4, 21) configured to determine possibility of the power supply based on a result of the determination by the vehicle position determination unit (4, 21); - a display unit configured to display a result of the determination by the supply possibility determination unit (4, 21) for an occupant of the vehicle; and - a distance measuring unit (25a, 25b) configured to measure the gap (Gap), - a vehicle position determination unit (4, 21) configured to determine a position of a vehicle relative to each of the a first region (α) and the second region (α+β); - a supply possibility determination unit (4, 21) configured to determine possibility of the power supply based on a result of the determination by the vehicle position determination unit (4, 21); - a display unit configured to display a result of the determination by the supply possibility determination unit (4, 21) for an occupant of the vehicle; and - a distance measuring unit (25a, 25b) configured to measure the gap (Gap), (i) to determine the possibility of the power supply based on a gap measurement value measured by the distance measuring unit (25a, 25b) and (ii) to determine that supply of power is possible when a measurement value of the gap (Gap) is between minimum (Zmin) and maximum (Zmax).