A non-contact power supply system comprising: a power supply device, which includes primary coils arranged on a power supply surface and configured to be excited at an operational frequency, and a power reception device, which includes a secondary coil configured to induce current using a resonance phenomenon based on alternating flux from the primary coils when arranged on the power supply surface, characterized in that: the power reception device further comprises a capacitor connected to the secondary coil; wherein a capacitance of the capacitor is adjusted to set a position of a resonance system for the operational frequency that excites the primary coil, wherein the operational frequency is set in the proximity of a resonance frequency of the resonance system that is formed when the secondary coil is located at an intermediate position between two of the primary coils that are adjacent to each other; wherein the proximity of the resonance frequency is a frequency region (fx-fy) between two intersecting points (fx,fy) of a resonance curve, which represents the resonance system formed when the secondary coil is located at the intermediate position, and a resonance curve, which represents a resonance system formed when the secondary coil is located at a directly opposed position at which the secondary coil is directly opposed to one of the primary coils, and when the operational frequency is set in the frequency region (fx-fy), an output power of the power reception device at the intermediate position is greater than or equal to an output power of the power reception device at the directly opposed position. a power supply device, which includes primary coils arranged on a power supply surface and configured to be excited at an operational frequency, and a power reception device, which includes a secondary coil configured to induce current using a resonance phenomenon based on alternating flux from the primary coils when arranged on the power supply surface, characterized in that: the power reception device further comprises a capacitor connected to the secondary coil; wherein a capacitance of the capacitor is adjusted to set a position of a resonance system for the operational frequency that excites the primary coil, wherein the operational frequency is set in the proximity of a resonance frequency of the resonance system that is formed when the secondary coil is located at an intermediate position between two of the primary coils that are adjacent to each other; wherein the proximity of the resonance frequency is a frequency region (fx-fy) between two intersecting points (fx,fy) of a resonance curve, which represents the resonance system formed when the secondary coil is located at the intermediate position, and a resonance curve, which represents a resonance system formed when the secondary coil is located at a directly opposed position at which the secondary coil is directly opposed to one of the primary coils, and when the operational frequency is set in the frequency region (fx-fy), an output power of the power reception device at the intermediate position is greater than or equal to an output power of the power reception device at the directly opposed position. the power reception device further comprises a capacitor connected to the secondary coil; wherein a capacitance of the capacitor is adjusted to set a position of a resonance system for the operational frequency that excites the primary coil, wherein the operational frequency is set in the proximity of a resonance frequency of the resonance system that is formed when the secondary coil is located at an intermediate position between two of the primary coils that are adjacent to each other; wherein the proximity of the resonance frequency is a frequency region (fx-fy) between two intersecting points (fx,fy) of a resonance curve, which represents the resonance system formed when the secondary coil is located at the intermediate position, and a resonance curve, which represents a resonance system formed when the secondary coil is located at a directly opposed position at which the secondary coil is directly opposed to one of the primary coils, and when the operational frequency is set in the frequency region (fx-fy), an output power of the power reception device at the intermediate position is greater than or equal to an output power of the power reception device at the directly opposed position.